CVE-2026-23903: apache software foundation apache shiro Authentication Bypass by Alternate Name

Vulnerability summary

CVE-2026-23903 is a medium (CVSS 5.3) Authentication Bypass by Alternate Name vulnerability in apache software foundation apache shiro. EPSS estimates a 0.40% chance of exploitation in the next 30 days, higher than 32.9% of scored vulnerabilities.

Timeline

1. 09-02-2026
   PublishedVulnerability first disclosed.
2. 20-08-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-289Authentication Bypass by Alternate NameThe product performs authentication based on the name of a resource being accessed, or the name of the actor performing the access, but it does not properly check all possible names for that resource or actor.