CVE-2026-23903

Authentication Bypass by Alternate Name vulnerability in Apache Shiro.

This issue affects Apache Shiro: before 2.0.7.

Users are recommended to upgrade to version 2.0.7, which fixes the issue.

The issue only effects static files. If static files are served from a case-insensitive filesystem,

such as default macOS setup, static files may be accessed by varying the case of the filename in the request.

If only lower-case (common default) filters are present in Shiro, they may be bypassed this way.

Shiro 2.1.0 and later has a new parameters to remediate this issue

shiro.ini: filterChainResolver.caseInsensitive = true

application.properties: shiro.caseInsensitive=true

Shiro 3.0.0 and later makes this the default in shiro.ini-based configurations.

Shiro 3.0.1 and later makes this the default in all configurations, including programmatic and Spring / Spring Boot.