Apache Shiro has an Authentication Bypass

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS

• CVE-2026-23903: 0.40% estimated exploitation activity in the next 30 days; percentile 34.52 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact Authentication Bypass: A vulnerability exists in Apache Shiro that allows authentication bypass for static files when served from a case-insensitive filesystem (such as the default configuration on macOS or Windows). The issue arises when Shiro's URL filters are configured with lower-case rules (a common default), but the underlying operating system treats mixed-case filenames as identical. An attacker can access protected static resources by varying the capitalization of the filename in the request (e.g., requesting /SECRET.TXT to bypass a rule for /secret.txt). This issue specifically affects static file handling and does not impact dynamic resource paths that are case-sensitive. Patches Users should upgrade to Apache Shiro 2.1.0 or later. Important Configuration Note: Version 2.1.0 introduces a new configuration parameter to handle case-insensitivity, which must be enabled manually to resolve the issue: shiro.ini: Spring Boot (application.properties): Note: Apache Shiro…

Published by the source

9 Feb 2026, 12:30 UTC

Last modified by the source

11 Feb 2026, 19:48 UTC

Source last checked

26 Oct 2026, 16:44 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-c244-p6m5-vqj6

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# Patch Next advisory brief: CVE-2026-23903

Advisory: Apache Shiro has an Authentication Bypass
IDs: CVE-2026-23903, GHSA-c244-p6m5-vqj6
Record: https://patchnext.com/advisories/cve-2026-23903 (revision 1, source checked 26 Oct 2026, 16:44 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.apache.shiro:shiro-spring 2.1.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.apache.shiro:shiro-spring: affected <= 2.0.6; fixed in 2.1.0

## Suggested inspection (read-only)
- Maven org.apache.shiro:shiro-spring: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.apache.shiro:shiro-spring.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-c244-p6m5-vqj6 (GitHub-reviewed advisory GHSA-c244-p6m5-vqj6 lists affected ranges: Maven org.apache.shiro:shiro-spring >=0 <=2.0.6)

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