CVE-2025-20127

highpriority · track · 0EPSS 0.007 · 52 %ileDEEUNLRUUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.67% (52nd) EPSS
CVSS 7.7 · high
Is it mine?
85 products
Check your exposure
Who says so?
6 sources
cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-26

A vulnerability in the TLS 1.3 implementation for a specific cipher for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software for Cisco Firepower 3100 and 4200 Series devices could allow an authenticated, remote attacker to consume resources that are associated with incoming TLS 1.3 connections, which eventually could cause the device to stop accepting any new SSL/TLS or VPN requests. This vulnerability is due to the implementation of the TLS 1.3 Cipher TLS_CHACHA20_POLY1305_SHA256. An attacker could exploit this vulnerability by sending a large number of TLS 1.3 connections with the specific TLS 1.3 Cipher TLS_CHACHA20_POLY1305_SHA256. A successful exploit could allow the attacker to cause a denial of service (DoS) condition where no new incoming encrypted connections are accepted. The device must be reloaded to clear this condition. Note: These incoming TLS 1.3 connections include both data traffic and user-management traffic. After the device is in the vulnerable state, no new encrypted connections can be accepted.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.1 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.1.5 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.10 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.10 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.21 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.21 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.22 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.22 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.4 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.4 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.7 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.7 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22.1.1 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22.1.1 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Threat Defense (FTD) Software 7.4.0 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Threat Defense (FTD) Software 7.4.1 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Threat Defense (FTD) Software 7.4.1 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Threat Defense (FTD) Software 7.4.1.1 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Threat Defense (FTD) Software 7.4.1.1 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Threat Defense (FTD) Software 7.4.2 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Threat Defense (FTD) Software 7.4.2 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Threat Defense (FTD) Software 7.4.2.1 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Threat Defense (FTD) Software 7.4.2.1 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Threat Defense (FTD) Software 7.6.0 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Threat Defense (FTD) Software 7.6.0 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.1 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.1.5 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.10 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.10 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.21 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.21 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.22 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.22 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.4 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.4 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.7 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.7 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22.1.1 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22.1.1 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Threat Defense (FTD) Software 7.4.0 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Threat Defense (FTD) Software 7.4.1 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Threat Defense (FTD) Software 7.4.1 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Threat Defense (FTD) Software 7.4.1.1 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Threat Defense (FTD) Software 7.4.1.1 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Threat Defense (FTD) Software 7.4.2 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Threat Defense (FTD) Software 7.4.2 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Threat Defense (FTD) Software 7.4.2.1 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Threat Defense (FTD) Software 7.4.2.1 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Threat Defense (FTD) Software 7.6.0 when installed on Cisco Secure Firewall 3100 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

  • WorkaroundCisco Secure Firewall Threat Defense (FTD) Software 7.6.0 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    There is a workaround that addresses this vulnerability. Use the no ssl cipher tlsv1.3 custom <cipher list> CLI command to remove the cipher. While this workaround has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

02

cvss

Technical severity, 0–10. One row per scoring source.

7.7
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.17.7highAV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU
v3.17.7highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:Hsecondary · ENISA EU
v3.17.7highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:Hsecondary · psirt@cisco.com USexploitability 3.1 · impact 4
v3.17.1highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)
v3.17.7highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:Hsecondary · NCSC-NL NL
v3.17.7highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:Hsecondary · Cisco PSIRT US
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-404USCWE-404USCWE-404US
05

affected products (85)

Products and version ranges known to be affected.

showing 20 of 85
06

advisories (3)

Vendor and ecosystem advisories describing this.

  • NCSC-2025-0264Kwetsbaarheden verholpen in Cisco Secure Firewall SoftwareNL2025-08-15csaf · ncsc_nlNL

    Cisco heeft meerdere kwetsbaarheden verholpen in Cisco Secure Firewall Software (inclusief ASA en FTD).

  • WID-SEC-W-2025-1839Cisco ASA und Secure Firewall Threat Defense: Mehrere SchwachstellenDeutsch2025-08-14csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in Cisco ASA (Adaptive Security Appliance) und Secure Firewall Threat Defense ausnutzen, um einen Denial of Service Angriff durchzuführen, um beliebige Kommandos mit Administratorrechten auszuführen, und um Sicherheitsvorkehrungen zu umgehen.

  • cisco-sa-3100_4200_tlsdos-2yNSCd54Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense Software for Firepower 3100 and 4200 Series TLS 1.3 Cipher Denial of Service Vulnerability2025-08-14csaf · cisco_csafUS

    A vulnerability in the TLS 1.3 implementation for a specific cipher for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software for Cisco Firepower 3100 and 4200 Series devices could allow an authenticated, remote attacker to consume resources that are associated with incoming TLS 1.3 connections, which eventually could cause the device to stop accepting any new SSL/TLS or VPN requests. This vulnerability is due to the implementation of the TLS 1.3 Cipher TLS_CHACHA20_POLY1305_SHA256. An attacker could exploit this vulnerability by sending a large number of TLS 1.3 connections with the specific TLS 1.3 Cipher TLS_CHACHA20_POLY1305_SHA256. A successful exploit could allow the attacker to cause a denial of service (DoS) condition where no new incoming encrypted connections are accepted. The device must be reloaded to clear this condition. Note: These incoming TLS 1.3 connections include both data traffic and user-management traffic. After the device is in the vulnerable state, no new encrypted connections can be accepted. Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability. This advisory is part of the August 2025 release of the Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: August 2025 Semiannual Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75415"].

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also known as (4)

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cnnvdenisa_euvdfstec_bducert_bundcisco_csafncsc_nlNVDCVE.orgMITRE
published 2025-08-14modified 2026-08-11
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references (4)

External citations — patches, advisories, analysis.

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