CVE-2026-20082

highpriority · track · 0EPSS 0.004 · 37 %ileDEEUNLUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.43% (37th) EPSS
CVSS 8.6 · high
Is it mine?
29 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · cert_bund · cisco_csaf

EPSS · scored 2026-10-26

A vulnerability in the handling of the embryonic connection limits in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to cause incoming TCP SYN packets to be dropped incorrectly. This vulnerability is due to improper handling of new, incoming TCP connections that are destined to management or data interfaces when the device is under a TCP SYN flood attack. An attacker could exploit this vulnerability by sending a crafted stream of traffic to an affected device. A successful exploit could allow the attacker to prevent all incoming TCP connections to the device from being established, including remote management access, Remote Access VPN (RAVPN) connections, and all network protocols that are TCP-based. This results in a denial of service (DoS) condition for affected features.

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 9.20.4.14 when installed on Cisco 3000 Series Industrial Security Appliances (ISA)cisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.4.14 when installed on Cisco Adaptive Security Virtual Appliance (ASAv)cisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.4.14 when installed on Cisco Firepower 1000 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.4.14 when installed on Cisco Firepower 2100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.4.14 when installed on Cisco Firepower 4100 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.4.14 when installed on Cisco Firepower 9000 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
  • FixedCisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.4.14 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 9.20.4.14 when installed on Cisco Secure Firewall 4200 Seriescisco_csaf

    Cisco has released software updates that address this vulnerability.

    https://software.cisco.com
02

cvss

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

8.6
010

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

v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · ENISA EU
v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · psirt@cisco.com USexploitability 3.9 · impact 4
v3.17.9highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)
v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · NCSC-NL NL
v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/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.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

05

affected products (29)

Products and version ranges known to be affected.

showing 20 of 29
06

advisories (3)

Vendor and ecosystem advisories describing this.

  • NCSC-2026-0077Kwetsbaarheden verholpen in Cisco Secure Firewall systemenNL2026-03-05csaf · ncsc_nlNL

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

  • WID-SEC-W-2026-0601Cisco ASA (Adaptive Security Appliance): Mehrere SchwachstellenDeutsch2026-03-04csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in Cisco ASA (Adaptive Security Appliance) ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um Dateien zu manipulieren, und um einen Denial of Service Angriff durchzuführen.

  • cisco-sa-asa-dos-FCvLD6vRCisco Secure Firewall Adaptive Security Appliance Software TCP Flood Denial of Service Vulnerability2026-03-04csaf · cisco_csafUS

    A vulnerability in the handling of the embryonic connection limits in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to cause incoming TCP SYN packets to be dropped incorrectly. This vulnerability is due to improper handling of new, incoming TCP connections that are destined to management or data interfaces when the device is under a TCP SYN flood attack. An attacker could exploit this vulnerability by sending a crafted stream of traffic to an affected device. A successful exploit could allow the attacker to prevent all incoming TCP connections to the device from being established, including remote management access, Remote Access VPN (RAVPN) connections, and all network protocols that are TCP-based. This results in a denial of service (DoS) condition for affected features. 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"].

07

also known as (3)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

09

references (4)

External citations — patches, advisories, analysis.

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