CVE-2026-20103A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure…

Description

A vulnerability in the Remote Access SSL VPN functionality of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust device memory resulting in a denial of service (DoS) condition to new Remote Access SSL VPN connections. This does not affect the management interface, though it may become temporarily unresponsive. This vulnerability is due to trusting user input without validation. An attacker could exploit this vulnerability by sending crafted packets to the Remote Access SSL VPN server. A successful exploit could allow the attacker to cause the device web interface to stop responding, resulting in a DoS condition.

Timeline

Scores

EPSS (exploitation in 30 days)

0.40% · top 65% of all CVEs (12 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.6.

Affected products

• Cisco · Cisco Secure Firewall Adaptive Security Appliance (ASA) Software

  • affected 9.12.4.48
  • affected 9.12.4.50
  • affected 9.12.4.52
  • affected 9.12.4.54
  • affected 9.12.4.55
  • affected 9.12.4.56
  • affected 9.12.4.58
  • affected 9.12.4.62
  • affected 9.12.4.65
  • affected 9.12.4.67
  • affected 9.16.3.15
  • affected 9.16.3.19
  • affected 9.16.3.23
  • affected 9.16.4
  • affected 9.16.4.9
  • affected 9.16.4.14
  • affected 9.16.4.19
  • affected 9.16.4.27
  • affected 9.16.4.38
  • affected 9.16.4.39
  • affected 9.16.4.42
  • affected 9.16.4.48
  • affected 9.16.4.55
  • affected 9.16.4.57
  • affected 9.16.4.61
  • affected 9.16.4.62
  • affected 9.16.4.67
  • affected 9.16.4.70
  • affected 9.16.4.71
  • affected 9.16.4.76
  • affected 9.16.4.82
  • affected 9.16.4.84
  • affected 9.17.1.20
  • affected 9.17.1.30
  • affected 9.17.1.33
  • affected 9.17.1.39
  • affected 9.17.1.45
  • affected 9.17.1.46
  • affected 9.18.1.3
  • affected 9.18.2
  • and 57 more

• Cisco · Cisco Secure Firewall Threat Defense (FTD) Software

  • affected 6.4.0.16
  • affected 6.4.0.17
  • affected 6.4.0.18
  • affected 7.0.4
  • affected 7.0.5
  • affected 7.0.6
  • affected 7.0.6.1
  • affected 7.0.6.2
  • affected 7.0.6.3
  • affected 7.0.7
  • affected 7.0.8
  • affected 7.0.8.1
  • affected 7.1.0.3
  • affected 7.2.1
  • affected 7.2.2
  • affected 7.2.3
  • affected 7.2.4
  • affected 7.2.4.1
  • affected 7.2.5
  • affected 7.2.5.1
  • affected 7.2.6
  • affected 7.2.7
  • affected 7.2.5.2
  • affected 7.2.8
  • affected 7.2.8.1
  • affected 7.2.9
  • affected 7.2.10
  • affected 7.2.10.2
  • affected 7.3.0
  • affected 7.3.1
  • affected 7.3.1.1
  • affected 7.3.1.2
  • affected 7.4.0
  • affected 7.4.1
  • affected 7.4.1.1
  • affected 7.4.2
  • affected 7.4.2.1
  • affected 7.4.2.2
  • affected 7.4.2.3
  • affected 7.4.2.4
  • and 7 more

What to do

Exploitation: The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-9441 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-20103](https://cveledger.app/badge/CVE-2026-20103.svg)](https://cveledger.app/cve/CVE-2026-20103)

Record last updated 4 Mar 2026, 21:36 UTC.