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GHSA-c244-p6m5-vqj6

MediumCVSS 5.3 / 10

Published Feb 9, 2026·Last modified Apr 9, 2026

Affected Components(0)

No affected components available

Description

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:

filterChainResolver.caseInsensitive = true

Spring Boot (application.properties):
```
shiro.caseInsensitive=true
```

Note: Apache Shiro 3.0.0 (upcoming) will enable this setting by default.

Workarounds

Ensure that the filesystem hosting the application is case-sensitive (e.g., Linux/Unix).
Manually configure all Shiro filter chains to handle all possible case variations of protected filenames (not recommended due to complexity).

Resources

Risk Scores

Base Score

5.3

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the confidentiality of the information.

Threat Intelligence

4.9

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS

N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit

Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Related Vulnerabilities

CVE-2026-23903
Alias
EUVD-2026-6903
Alias

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Medium severity

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