CVE-2026-15634 IBM WebSphere Application Server and IBM WebSphere Application Server - Liberty Request Smuggling
Attackers can exploit HTTP request smuggling to poison caches, bypass firewalls, and conduct XSS attacks on IBM WebSphere Application Server.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-15634?
CVE-2026-15634 is a medium-severity vulnerability in IBM WebSphere Application Server, published on 14 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
IBM WebSphere Application Server 8.5 and 9.0, and IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.8 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.
Weakness: CWE-444
Which versions are affected by CVE-2026-15634?
How do I fix CVE-2026-15634?
No fix has been published for CVE-2026-15634 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-15634 being exploited?
There is no known exploitation of CVE-2026-15634 in the wild and no public exploit code.
Sources
Also known as GHSA-mq4f-p367-w4xc.