Buffer overflow in IBM Aix

CVE-2026-16855

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.

Vulnerability class: Buffer Overflow

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Affected products

Ibm Aix — versions 7.2, 7.3
Ibm Powervm Vios — versions 4.1

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

psirt@us.ibm.com (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-16855?: CVE-2026-16855 is a medium-severity vulnerability in IBM Aix, classified under Out-of-bounds Write. CVSS score: 5.5/10. Published 2026-08-19.
How severe is CVE-2026-16855?: Medium severity. CVSS v3 base score is 5.5 out of 10.