What is CVE-2026-18828?

CVE-2026-18828 is a medium-severity vulnerability in IBM Aix, classified under Out-of-bounds Write. CVSS score: 5.4/10. Published 2026-08-20.

How severe is CVE-2026-18828?

Medium severity. CVSS v3 base score is 5.4 out of 10.

Buffer overflow in IBM Aix

CVE-2026-18828

IBM AIX 7.2, and 7.3 and IBM PowerVM VIOS 4.1 could allow a remote attacker to cause a denial of service due to a stack-based buffer overflow.

Vulnerability class: Buffer Overflow

Published 2026-08-20 · last modified 2026-08-25.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L.

EPSS exploit prediction

EPSS: 0.004 (28.2th percentile), scored 2026-10-06.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 28.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

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

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

www.ibm.com/support/pages/node/7283858 (vendor-advisory, Patch, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-18828?: CVE-2026-18828 is a medium-severity vulnerability in IBM Aix, classified under Out-of-bounds Write. CVSS score: 5.4/10. Published 2026-08-20.
How severe is CVE-2026-18828?: Medium severity. CVSS v3 base score is 5.4 out of 10.