CVE-2026-16855 Vulnerabilities in IBM AIX and PowerVM VIOS

Medium 5.5 Published 19 Aug 2026 Updated 20 Aug 2026

A local attacker can cause a denial of service in IBM AIX and PowerVM VIOS via a heap buffer overflow.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-16855?

CVE-2026-16855 is a medium-severity memory corruption vulnerability in Ibm Aix, published on 19 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

IBM AIX 7.2, and 7.3 and IBM PowerVM VIOS 4.1 could allow a local attacker to cause a denial of service due to a heap buffer overflow.

Weakness: CWE-787

Which versions are affected by CVE-2026-16855?

It affects 2 products.

Products include Ibm Aix, Ibm Vios.

How do I fix CVE-2026-16855?

No fix has been published for CVE-2026-16855 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-2026-16855 being exploited?

There is no known exploitation of CVE-2026-16855 in the wild and no public exploit code.

All Ibm Aix vulnerabilities

Sources

Also known as GHSA-r7x9-3h4v-9mc9.