CVE-2026-20335 Integer overflow in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
Cisco firewall software contains incorrect calculation flaws that could lead to denial of service or undefined behavior, requiring a security patch.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-20335?
CVE-2026-20335 is a high-severity vulnerability in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-682
Which versions are affected by CVE-2026-20335?
How do I fix CVE-2026-20335?
No fix has been published for CVE-2026-20335 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-20335 being exploited?
There is no known exploitation of CVE-2026-20335 in the wild and no public exploit code.
Sources
Also known as GHSA-vcgm-f86r-xmp4.