How to Fix CVE-2026-20106: Cisco Secure Firewall Adaptive Security Appliance (ASA) Software (Bundle Sibling)
By Sai Kiran Pandrala. Last verified: 2026-05-25.
CVE-2026-20106 is a sibling vulnerability in the same vendor advisory as CVE-2026-20100. Apply the same patched build and you close both. The technical detail below is what differs.
⚡ At a glance
| Severity | 5.3 (Medium) |
|---|---|
| Actively exploited? | No public listing in CISA KEV |
| Affected | Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.1; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.1.2; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.1.3; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.2; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.2.4; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.2.5; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.2.9; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.3; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.3.2; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.3.7; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.3.12; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.3.9; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.2.1; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.2; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.4; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.7; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.10; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.13; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.8; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.18; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.24; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.26; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.29; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.30; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.35; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.37; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.38; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.39; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.40; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.41; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.47; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.48; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.50; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.52; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.54; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.55; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.56; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.58; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.62; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.65; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.12.4.67; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.1; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.1.28; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.2; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.2.3; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.2.7; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.2.11; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.2.13; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.2.14; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.3; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.3.3; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.3.14; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.3.15; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.3.19; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.3.23; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.9; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.14; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.19; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.27; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.38; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.39; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.42; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.48; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.55; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.57; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.61; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.62; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.67; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.70; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.71; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.76; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.82; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.16.4.84; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17.1; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17.1.7; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17.1.9; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17.1.10; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17.1.11; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17.1.13; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17.1.15; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17.1.20; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17.1.30; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17.1.33; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17.1.39; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17.1.45; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.17.1.46; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.1; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.1.3; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.2; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.2.5; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.2.7; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.2.8; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.3; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.3.39; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.3.46; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.3.53; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.3.55; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.3.56; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.4; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.4.5; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.4.8; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.4.22; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.4.24; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.4.29; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.4.34; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.4.40; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.4.47; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.4.50; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.4.52; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.4.53; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.18.4.57; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19.1; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19.1.5; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19.1.9; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19.1.12; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19.1.18; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19.1.22; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19.1.24; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19.1.27; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19.1.28; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19.1.31; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19.1.37; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19.1.38; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.19.1.42; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.1; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.1.5; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.10; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.21; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.2.22; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.4; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.7; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.9; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.10; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.13; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.16; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.20.3.20; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22.1.1; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22.1.3; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22.1.2; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22.1.6; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.22.2; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.23.1; Cisco Secure Firewall Adaptive Security Appliance (ASA) Software 9.23.1.3; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.1; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.3; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.2; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.4; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.5; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.6; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.7; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.8; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.9; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.10; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.11; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.12; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.13; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.14; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.15; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.16; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.17; Cisco Secure Firewall Threat Defense (FTD) Software 6.4.0.18; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.0; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.0.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.1.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.2; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.2.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.3; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.4; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.5; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.6; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.6.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.6.2; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.6.3; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.7; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.8; Cisco Secure Firewall Threat Defense (FTD) Software 7.0.8.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.1.0; Cisco Secure Firewall Threat Defense (FTD) Software 7.1.0.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.1.0.2; Cisco Secure Firewall Threat Defense (FTD) Software 7.1.0.3; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.0; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.0.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.2; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.3; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.4; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.4.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.5; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.5.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.6; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.7; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.5.2; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.8; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.8.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.9; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.10; Cisco Secure Firewall Threat Defense (FTD) Software 7.2.10.2; Cisco Secure Firewall Threat Defense (FTD) Software 7.3.0; Cisco Secure Firewall Threat Defense (FTD) Software 7.3.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.3.1.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.3.1.2; Cisco Secure Firewall Threat Defense (FTD) Software 7.4.0; Cisco Secure Firewall Threat Defense (FTD) Software 7.4.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.4.1.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.4.2; Cisco Secure Firewall Threat Defense (FTD) Software 7.4.2.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.4.2.2; Cisco Secure Firewall Threat Defense (FTD) Software 7.4.2.3; Cisco Secure Firewall Threat Defense (FTD) Software 7.4.2.4; Cisco Secure Firewall Threat Defense (FTD) Software 7.6.0; Cisco Secure Firewall Threat Defense (FTD) Software 7.6.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.6.2; Cisco Secure Firewall Threat Defense (FTD) Software 7.6.2.1; Cisco Secure Firewall Threat Defense (FTD) Software 7.7.0; Cisco Secure Firewall Threat Defense (FTD) Software 7.7.10; Cisco Secure Firewall Threat Defense (FTD) Software 7.7.10.1 |
| Fixed in | Same patched build as CVE-2026-20100 |
| Type (CWE) | CWE-401: Missing Release of Memory after Effective Lifetime |
What's different about CVE-2026-20106?
A vulnerability in the Remote Access SSL VPN, HTTP management and MUS 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 requiring a manual reboot.
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 to stop responding, resulting in a DoS condition.
How to fix CVE-2026-20106
Apply the patched build per the primary write-up: How to Fix CVE-2026-20100. All commands, verification steps, and rollback notes for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software are listed there.
Frequently asked questions
Does the CVE-2026-20100 patch close CVE-2026-20106?
Yes. Both CVEs are addressed by the same vendor patch. Applying the patched build closes the full bundle.
Is CVE-2026-20106 listed in CISA KEV?
No public KEV listing at the time of this writing.
Where is the official advisory?
See https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-vpn-m9sx6MbC
References
- Official vendor advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-vpn-m9sx6MbC
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-20106
- CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- Primary: How to Fix CVE-2026-20100
*Written by Sai Kiran Pandrala. Part of the Cisco Secure Firewall Adaptive Security Appliance (ASA) Software bundle. Full procedure at how-to-fix-cve-2026-20100.*