CVE-2026-23903 Apache Shiro: Auth bypass when accessing static files only on case-insensitive filesystems
Attackers can bypass authentication filters for static files on case-insensitive filesystems by varying filename case, requiring an upgrade to Apache Shiro.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-23903?
CVE-2026-23903 is a medium-severity authentication bypass vulnerability in Apache Shiro, published on 9 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-289
Which versions are affected by CVE-2026-23903?
2 open source packages ship an affected version, including org.apache.shiro:shiro-spring. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
org.apache.shiro:shiro-spring Maven | All versions | 2.1.0 |
org.apache.shiro:shiro-spring Maven | All versions | 2.1.0 |
Products include Apache Shiro.
How do I fix CVE-2026-23903?
Upgrade org.apache.shiro:shiro-spring to 2.1.0 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-23903 being exploited?
There is no known exploitation of CVE-2026-23903 in the wild and no public exploit code.
Other vulnerabilities in Apache Shiro
- CVE-2023-34478 Path Traversal in Apache Shiro
- CVE-2022-40664 Authentication Bypass Vulnerability in Shiro when forwarding or including via RequestDispatcher
- CVE-2022-32532 Authentication Bypass Vulnerability
- CVE-2021-41303 Apache Shiro vulnerable to a specially crafted HTTP request causing an authentication bypass
- CVE-2020-17523 Authentication bypass in Apache Shiro
Sources
Also known as CLEANSTART-2026-KG68344, DEBIAN-CVE-2026-23903, ECHO-b110-6f36-d7d3, GHSA-c244-p6m5-vqj6, MINI-8hqw-44pm-cw2q, MINI-cprq-98f5-2h6r and 5 more.