CVE-2025-31650

Improper Input Validation vulnerability in Apache Tomcat. Incorrect error handling for some invalid HTTP priority headers resulted in incomplete clean-up of the failed request which created a memory leak. A large number of such requests could trigger an OutOfMemoryException resulting in a denial of service. This issue affects Apache Tomcat: from 9.0.76 through 9.0.102, from 10.1.10 through 10.1.39, from 11.0.0-M2 through 11.0.5.
The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.90 though 8.5.100. Users are recommended to upgrade to version 9.0.104, 10.1.40 or 11.0.6 which fix the issue.

A flaw was found in Apache Tomcat. This vulnerability allows an application-level denial of service (DoS), causing it to become unresponsive or slow via maliciously crafted HTTP/2 prioritization headers. It performs an incomplete cleanup of failed requests, which triggers a memory leak.

It was discovered that Tomcat did not correctly handle case sensitivity. An attacker could possibly use this issue to bypass authentication mechanisms. Elysee Franchuk discovered that Tomcat did not correctly limit the number of attributes for a session. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 24.04 LTS.