CVE-2026-76459 Cisco NX-OS Software Security Hardening Release: October 2026 - Out-of-bounds Write Vulnerabilities
Out-of-bounds write vulnerabilities in Cisco NX-OS allow attackers to execute arbitrary code or cause denial of service.
- 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-2026-76459?
CVE-2026-76459 is a critical memory corruption vulnerability in Cisco NX-OS Software, published on 7 Oct 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 NX-OS 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-2026-76459 are related to out-of-bounds write issues that are grouped under the Common Weakness Enumeration (CWE) CWE-787.
Weakness: CWE-787
Which versions are affected by CVE-2026-76459?
How do I fix CVE-2026-76459?
No fix has been published for CVE-2026-76459 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-76459 being exploited?
There is no known exploitation of CVE-2026-76459 in the wild and no public exploit code.
Sources
Also known as GHSA-7c6x-33hj-4wv3.