CVE-2025-31651 Apache Tomcat: Bypass of rules in Rewrite Valve

What is CVE-2025-31651?

CVE-2025-31651 is a critical vulnerability in Apache Tomcat, published on 28 Apr 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Improper Neutralization of Escape, Meta, or Control Sequences vulnerability in Apache Tomcat. For a subset of unlikely rewrite rule configurations, it was possible for a specially crafted request to bypass some rewrite rules. If those rewrite rules effectively enforced security constraints, those constraints could be bypassed.

This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.5, from 10.1.0-M1 through 10.1.39, from 9.0.0.M1 through 9.0.102. The following versions were EOL at the time the CVE was created but are known to be affected: 8.5.0 though 8.5.100. Other, older, EOL versions may also be affected.

Users are recommended to upgrade to version [FIXED_VERSION], which fixes the issue.

Weakness: CWE-116

Which versions are affected by CVE-2025-31651?

17 open source packages ship an affected version, including org.apache.tomcat.embed:tomcat-embed-core, tomcat and org.apache.tomcat:tomcat-catalina. It affects 1 product.

Products include Apache Tomcat.

How do I fix CVE-2025-31651?

Upgrade org.apache.tomcat.embed:tomcat-embed-core to a fixed version for your release line: 10.1.40, 11.0.6 or 9.0.104.

Is CVE-2025-31651 being exploited?

There is no known exploitation of CVE-2025-31651 in the wild and no public exploit code.

Public exploit code: 2 proofs of concept on GitHub.

Other vulnerabilities in Apache Tomcat

• CVE-2025-24813 Apache Tomcat Path Equivalence Exploited Critical 10.0
• CVE-2016-8735 Apache Tomcat Remote Code Execution Exploited Critical 9.8
• CVE-2017-12617 Apache Tomcat Remote Code Execution Exploited High 8.1
• CVE-2017-12615 Apache Tomcat on Windows Remote Code Execution Exploited High 8.1
• CVE-2026-34486 Apache Tomcat Missing Encryption of Sensitive Data Exploited High 7.5

All Apache Tomcat vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-tomcat-2025-31651, CLEANSTART-2026-EV68545, CLSA-2025-1750780819, CLSA-2025-1750785145, CLSA-2025-1752087582, CLSA-2025-1761576180 and 10 more.