Cisco Secure Firewall Threat Defense Software Snort 3 SSL Memory Management Denial of Service Vulnerability
A vulnerability in the memory management handling for the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart. This vulnerability is due to a logic error in memory management when a device is performing Snort 3 SSL packet inspection. An attacker could exploit this vulnerability by sending crafted SSL packets through an established connection to be parsed by the Snort 3 Detection Engine. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when the Snort 3 Detection Engine unexpectedly restarts. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is part of the March 2026 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: March 2026 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-75736"].
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-20052US | — | — | ||
A vulnerability in the memory management handling for the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote att… | ||||
references
External citations — patches, advisories, analysis.
- Security Vulnerability Policyexternal
- Cisco Defense Orchestrator documentation.external
- Cisco Secure Firewall Threat Defense Software Snort 3 SSL Memory Management Denial of Service Vulnerabilityself
- Cisco Security Vulnerability Policyexternal
- Security Impact Rating (SIR)external
- considering software upgradesexternal
- Cisco Software Checkerexternal
- Cisco Event Response: March 2026 Cisco Secure Firewall ASA, Secure FMC, and Secure FTD Software Security Advisory Bundled Publicationexternal
remediations (41)
- FixedCisco Secure Firewall Threat Defense (FTD) Software 7.4.0 when installed on Cisco Secure Firewall 4200 Series
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 3000 Series Industrial Security Appliances (ISA)
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 Firepower 1000 Series
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 Firepower 2100 Series
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 Firepower 4100 Series
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 Firepower 9000 Series
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 Series
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 Series
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 Threat Defense Virtual
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 3000 Series Industrial Security Appliances (ISA)
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 Firepower 1000 Series
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 Firepower 2100 Series
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 Firepower 4100 Series
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 Firepower 9000 Series
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 Series
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 Series
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 Threat Defense Virtual
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 3000 Series Industrial Security Appliances (ISA)
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 Firepower 1000 Series
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 Firepower 2100 Series
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 Firepower 4100 Series
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 Firepower 9000 Series
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 Series
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 Series
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 Threat Defense Virtual
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 3000 Series Industrial Security Appliances (ISA)
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 Firepower 1000 Series
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 Firepower 2100 Series
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 Firepower 4100 Series
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 Firepower 9000 Series
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 Series
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 Series
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 Threat Defense Virtual
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 3000 Series Industrial Security Appliances (ISA)
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 Firepower 1000 Series
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 Firepower 4100 Series
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 Firepower 9000 Series
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 1200 Series
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 Series
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 Series
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 Threat Defense Virtual
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
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