LockOutRealm Case-Sensitivity Flaw in Tomcat 711 before Fix
CVE-2026-43513 Published on May 12, 2026
Apache Tomcat: LockOutRealm treats user names as case-sensitive
Improper Handling of Case Sensitivity vulnerability in LockOutRealm in Apache Tomcat.
This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.21, from 10.1.0-M1 through 10.1.54, from 9.0.0.M1 through 9.0.117, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109.
Older unsupported versions may also be affected.
Users are recommended to upgrade to version 11.0.22, 10.1.55 or 9.0.118 which fix the issue.
Vulnerability Analysis
CVE-2026-43513 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and availability.
Weakness Type
Improper Handling of Case Sensitivity
The software does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.
Products Associated with CVE-2026-43513
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Affected Versions
Apache Software Foundation Apache Tomcat:- Version 11.0.0-M1, <= 11.0.21 is affected.
- Version 10.1.0-M1, <= 10.1.54 is affected.
- Version 9.0.0.M1, <= 9.0.117 is affected.
- Version 8.5.0, <= 8.5.100 is affected.
- Version 7.0.0, <= 7.0.109 is affected.
- Before 7.00 is unknown.