CVE-2026-8855: IBM HTTP Server

Critical severity, CVSS 9.8. EPSS: 0.8% chance of exploitation in the next 30 days.

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).

Affected products

• IBM HTTP Server: from 8.5.0.0, before 8.5.5.30 (fixed in 8.5.5.30); from 9.0.0.0, before 9.0.5.29 (fixed in 9.0.5.29)

Published 2026-05-26. Last modified 2026-07-23.