Improper Handling of Case Sensitivity in Apache Tomcat - CVE-2026-43513
Published: May 12, 2026
Vulnerability identifier: #VU131179
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-43513
CWE-ID: CWE-178
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Apache Foundation
Affected software:
Apache Tomcat
Apache Tomcat
Detailed vulnerability description
The vulnerability allows a remote attacker to weaken brute-force protection against a user's password.
The vulnerability exists due to improper input handling in LockOutRealm when processing case-insensitive user names. A remote attacker can vary the case of a user name during authentication attempts to weaken brute-force protection against a user's password.
This affects Realms where user names are treated as case insensitive.
How to mitigate CVE-2026-43513
Install security update from vendor's website.