CVE-2025-31651: tomcat Improper Encoding — Fix

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.

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CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-116 CWE-116

Affected Products

Vendor	Product	Versions
apache	tomcat	9.0.0 — 9.0.104
apache	tomcat	10.1.0 — 10.1.40
apache	tomcat	11.0.0 — 11.0.6

References

Advisories & Patches

https://lists.apache.org/[email protected]

Other References

http://www.openwall.com/lists/oss-security/2025/04/28/3 https://lists.debian.org/debian-lts-announce/2025/07/msg00009.html

Frequently Asked Questions

What is CVE-2025-31651? +

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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2025-31651? +

CVE-2025-31651 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.

What products are affected by CVE-2025-31651? +

CVE-2025-31651 affects products from apache, specifically: tomcat. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-31651? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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