CVE-2026-43513

Description

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.

How to fix CVE-2026-43513

To remediate CVE-2026-43513, upgrade the affected package to a fixed version below.

• —upgrade to 10.1.55 or later
• —no fix listed
• —no fix listed
• —upgrade to 9.0.70-2 or later
• —upgrade to 9.0.118 or later
• —upgrade to 9.0.118 or later
• —upgrade to 9.0.118 or later

Is CVE-2026-43513 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (7)

• >= 10.1.0, < 10.1.55, >= 11.0.0, < 11.0.22, >= 9.0.0, < 9.0.118
• from 0
• from 0
• from 0, < 9.0.70-2
• from 0, < 9.0.118
• from 0, < 9.0.118
• from 0, < 9.0.118

CVSS scores

References (11)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2026-43513
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2026-43513
• PATCHgithub.com/apache/tomcat
• WEBgithub.com/apache/tomcat/commit/4a90d3fa93988c447cd5bb7482f76ff70d7f15c2