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CVE-2026-20330

CRITICAL 9.9 ALL-YEARS

Published 2026-09-16 · Last modified 2026-09-18 · cisco · NVD: Awaiting Analysis

As 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-2026-20330 are related to improper neutralization issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-707.

ELEVATED IMPACT

Severe if exploited (CVSS 9.9), but no confirmed exploitation. Patch on a normal cadence.

Exploitation likelihood

0.3%chance of exploitation in 30 days · 25th percentile

○ In CISA KEV○ Public exploit / PoC◆ SSVC: exploitation none, automatable no

Impact if exploited

9.9CVSS 3.1 · CRITICAL · CNA

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ⚠Privileges: Requires a low-privilege account
  • ✓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-707: Improper Neutralization

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

All CVSS metrics

  • CRITICAL 9.9 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
  • CRITICAL 9.9 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Sources: NVD · CVE.org · EPSS