What is CVE-2026-8855?

CVE-2026-8855 is a high-severity vulnerability in IBM Aix, classified under Code Injection. CVSS score: 8.1/10. Published 2026-05-26.

How severe is CVE-2026-8855?

High severity. CVSS v3 base score is 8.1 out of 10.

RCE in IBM Aix

CVE-2026-8855

IBM HTTP Server 8.5, and 9.0 is vulnerable to remote code execution and denial of service in configurations with TLS mutual authentication (client authentication).

Vulnerability class: RCE (Remote Code Execution)

Published 2026-05-26 · last modified 2026-07-23.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.008 (57.3th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 57th percentile — 57.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.008 · change: +0.004

Affected products

Weakness classification (CWE)

CWE-94 — Code Injection

References

www.ibm.com/support/pages/node/7274065 (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-8855?: CVE-2026-8855 is a high-severity vulnerability in IBM Aix, classified under Code Injection. CVSS score: 8.1/10. Published 2026-05-26.
How severe is CVE-2026-8855?: High severity. CVSS v3 base score is 8.1 out of 10.