CVE-2026-20331
CRITICAL 9.6 ALL-YEARSAs part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Secure Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense Software and Cisco Secure Firewall Management Center Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20331 are related to the failure of protection mechanisms issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-693.
Severe if exploited (CVSS 9.6), but no confirmed exploitation. Patch on a normal cadence.
Exploitation likelihood
0.2%chance of exploitation in 30 days · 13th percentile
Impact if exploited
9.6CVSS 3.1 · CRITICAL · CNA
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityLow
What an attacker needs
- ⚠Access: Must sit on the same / adjacent network
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
No public exploit or proof-of-concept code is catalogued for this CVE (no ExploitDB, Nuclei, or CISA-KEV entry). It may still exist — search GitHub or check the references below.
Affected
Vendors Cisco
Products Cisco Secure Firewall Adaptive Security Appliance (Asa) Software Cisco Secure Firewall Management Center (Fmc) Cisco Secure Firewall Threat Defense (Ftd) Software
Weakness (CWE)
- CWE-693: Protection Mechanism Failure
CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L
All CVSS metrics
- CRITICAL 9.6 v3.1 · CNA Primary
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L - CRITICAL 9.6 v3.1 · NVD Secondary
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L