CVE-2026-86350 Apache Tomcat: Regression in fix for CVE-2026-41293 can trigger request header mix-up
Attackers can exploit HTTP/2 request smuggling to cause header mix-ups, potentially bypassing security controls or accessing sensitive data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-86350?
CVE-2026-86350 is a critical vulnerability in Apache Tomcat, published on 23 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Inconsistent interpretation of HTTP/2 requests ('HTTP Request/Response smuggling') vulnerability in Apache Tomcat caused by a regression in fix for CVE-2026-41293 can trigger request header mix-up.
This issue affects Apache Tomcat: from 11.0.22 through 11.0.25, from 10.1.55 through 10.1.59, from 9.0.118 through 9.0.121.
Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.
Weakness: CWE-444
Which versions are affected by CVE-2026-86350?
1 open source package ship an affected version, including tomcat.
| Package | Affected | Fixed in |
|---|---|---|
tomcat Bitnami | From 9.0.118 | 9.0.122, 10.1.60, 11.0.26 |
How do I fix CVE-2026-86350?
Upgrade tomcat to a fixed version for your release line: 9.0.122, 10.1.60 or 11.0.26.
Is CVE-2026-86350 being exploited?
There is no known exploitation of CVE-2026-86350 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as BIT-tomcat-2026-86350, DEBIAN-CVE-2026-86350, GHSA-6ff5-mwrj-376m, MINI-3j98-cpmc-m3xw, MINI-7gxq-q4x9-fv9h, MINI-rpfm-wwhq-525v and 1 more.