CVE-2026-65927: CWE-193 Off-by-one Error in Apache Software Foundation Apache Tomcat
Description
An off-by-one error vulnerability in Apache Tomcat's rewrite valve processing causes the rewrite to restart at the second rule instead of the first. This affects multiple versions of Apache Tomcat, including 11.0.0-M1 through 11.0.24, 10.1.0-M1 through 10.1.57, 9.0.0.M1 through 9.0.120, and some older 8.5.x versions. The issue is fixed in versions 11.0.25, 10.1.58, and 9.0.121.
CVSS v3.1
Score 7.5high
Affected software
Apache Software Foundation
Apache Tomcat
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-65927 is an off-by-one error (CWE-193) in Apache Tomcat's rewrite valve implementation. Specifically, the [N] flag causes rewrite processing to restart at the second rule rather than the first, which is unintended behavior. This affects Apache Tomcat versions from 11.0.0-M1 through 11.0.24, 10.1.0-M1 through 10.1.57, 9.0.0.M1 through 9.0.120, and also 8.5.0 through 8.5.100 (EOL versions). The vendor recommends upgrading to 11.0.25, 10.1.58, or 9.0.121 to address the issue.
Potential Impact
The vulnerability causes improper rewrite processing which may lead to denial of service (as indicated by the CVSS vector showing high impact on availability). There is no confidentiality or integrity impact reported. No known exploits in the wild have been documented at this time.
Mitigation Recommendations
Users should upgrade affected Apache Tomcat versions to 11.0.25, 10.1.58, or 9.0.121 where the issue is fixed. No other mitigation or temporary workaround is indicated. Patch status is confirmed by the vendor's recommended upgrade versions.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- apache
- Date Reserved
- 2026-07-23T14:24:12.608Z
- State
- PUBLISHED
Threat ID: 6a8e123aacd9273b49c467ff
Added to database: 08/25/2026, 22:07:54 UTC
Last enriched: 09/08/2026, 13:12:36 UTC
Last updated: 10/09/2026, 06:48:18 UTC
Views: 76
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