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CVE-2026-20335

Cisco Secure Adaptive Security Appliance Software, Secure Firewall Threat Defense Software and Secure Firewall Management Center Software Hardening Release - Incorrect Calculation Vulnerabilities

Published: Sep 16, 2026Updated: Sep 18, 2026 Sources: CVE List NVDCWE-682
8.1HIGH
NVD MITRE
EPSS Score
0.3%
Top 79.1%
CISA KEV
Not in KEV
Exploits
0 Known
Remediation
No Fix Available
Self-Check
Not available

Description

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-2026-20335 are related to incorrect calculation issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-682.

In plain language

AI Act now

A public attack method is available for Cisco Secure Firewall ASA, FTD, and FMC software, so businesses using these products should treat this as urgent; Cisco has not published a fixed version.

Executive summary

CVE-2026-20335 is a CVSS 8.1 network-reachable, unauthenticated vulnerability group involving incorrect calculations in Cisco Secure Firewall ASA, FTD, and FMC software.

If affected, business impact
Firewall management takeoverNetwork security disruptionSensitive data exposureBusiness service outages

What to do now

  1. Check whether your organization runs Cisco Secure Firewall ASA, FTD, or FMC, including appliances managed by an IT provider.
  2. Ask Cisco or your support provider whether your installed release is affected and whether any mitigation is available.
  3. Cisco has not published a fixed version for CVE-2026-20335; apply Cisco’s release guidance as soon as it is issued.
May need vendor / contractor work

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:HI:HA:H
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
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Weaknesses

CWE-682

Affected Products

Cisco
commercial·USaka cisco systems, cisco systems inc.
Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
Networking Infrastructure
Cisco Secure Firewall Management Center (FMC)
Networking Infrastructure
Cisco Secure Firewall Threat Defense (FTD) Software
Networking Infrastructure

Exploitability

0 exploit sources identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

View exploit details
Is your org exposed to CVE-2026-20335?Request an assessment to establish which checks are appropriate for your systems. Check my exposure

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-asaftdfmc-uvpPROhN
sec.cloudapps.cisco.com
News mentions
1

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