CVE-2026-15396: IBM WebSphere Application Server

Medium severity, CVSS 6.5. EPSS: 0.3% chance of exploitation in the next 30 days.

IBM WebSphere Application Server 9.0, and 8.5 and IBM WebSphere Application Server - Liberty are vulnerable to HTTP request smuggling, caused by improper parsing of the HTTP transfer-encoding request header. By sending a specially crafted HTTP transfer-encoding request header, an attacker could exploit this vulnerability to poison the web cache, bypass web application firewall protection, and conduct XSS attacks.

Affected products

• IBM WebSphere Application Server: version 9.0 only; version 8.5 only

Published 2026-09-14. Last modified 2026-09-16.