# CVE-2026-23903: Apache Shiro: Auth bypass when accessing static files only on case-insensitive filesystems

Status: published. Published: 2026-02-09. Updated: 2026-11-10.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Apache Software Foundation / Apache Shiro (org.apache.shiro:shiro-web): ≥ 0; < 2.0.7 (affected, semver). Source: CNA: apache

## Severity and prioritization

- CVSS 3.1: 5.3 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N; source: ADP: CISA-ADP

- CISA KEV: No listing in collected sources

- EPSS: 0.40% as of 2026-11-09; percentile 34.23%

- SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-289

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://lists.apache.org/thread/5jjf0hnjcol58z2m5y255c7scz1lnp8k (CNA: apache; vendor-advisory)

- http://www.openwall.com/lists/oss-security/2026/02/08/1 (ADP: CVE)

## Provenance

- CNA: apache: https://www.cve.org/CVERecord?id=CVE-2026-23903; retrieved 2026-11-10; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-23903; retrieved 2026-11-10; source updated Not reported

Revision: 977eb9d2b52bb0472d9a6ca8f2689a7fc7881b31a6580d53237bf45ffcb05a2f

Canonical: https://y2.dev/cve/CVE-2026-23903

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