# CVE-2026-23903

## Summary

- **CVE ID:** CVE-2026-23903
- **Severity:** MEDIUM
- **CVSS Score:** 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N)
- **CWE:** CWE-289
- **Published:** Feb 9, 2026
- **Last Modified:** Aug 20, 2026

## 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 2.0.7 and later has a new parameters to remediate this issue
shiro.ini: filterChainResolver.caseInsensitive = true
application.propertie: shiro.caseInsensitive=true

Shiro 3.0.0 and later (upcoming) makes this the default.

## Affected Products

- Apache Software Foundation — Apache Shiro (0)

## References

- [CNA](https://lists.apache.org/thread/5jjf0hnjcol58z2m5y255c7scz1lnp8k)
- [CVE](http://www.openwall.com/lists/oss-security/2026/02/08/1)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.36%
- **EPSS Percentile:** 28.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._