CVE-2026-59083 Apache Tomcat: Incorrect URL decoding in RewriteValve may allow security control bypass

What is CVE-2026-59083?

CVE-2026-59083 is a critical vulnerability in Apache Tomcat, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Improper Handling of URL Encoding (Hex Encoding) vulnerability in Apache Tomcat's rewrite valve allowed security constraint bypass for some configurations.

This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.23, from 10.1.0-M1 through 10.1.56, from 9.0.0.M1 through 9.0.119, from 8.5.0 through 8.5.100. Other versions that have reached end of support may also be affected.

Users are recommended to upgrade to version 11.0.24, 10.1.57 or 9.0.120, which fix the issue.

Weakness: CWE-177

Which versions are affected by CVE-2026-59083?

1 open source package ship an affected version, including tomcat. It affects 1 product.

Products include Apache Tomcat.

How do I fix CVE-2026-59083?

Upgrade tomcat to a fixed version for your release line: 9.0.120, 10.1.57 or 11.0.24.

Is CVE-2026-59083 being exploited?

There is no known exploitation of CVE-2026-59083 in the wild and no public exploit code.

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-2026-59083, CLSA-2026-1784625369, CLSA-2026-1786352989, DEBIAN-CVE-2026-59083, GHSA-hcjr-322h-429r, MINI-9mc4-v32g-r3fm and 3 more.