What’s Vulnerable › Vulnerabilities

CVE-2026-41661: Admidio: Reflected XSS in msg_window.php via Square Bracket to HTML Tag Conversion

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-07 · updated 2026-06-17
• Weakness: CWE-79

Description

Admidio is an open-source user management solution. Prior to version 5.0.9, an unauthenticated attacker can execute arbitrary JavaScript in any Admidio user's browser through a reflected XSS in system/msg_window.php. The endpoint passes user input through htmlspecialchars(), which does not encode square brackets. A subsequent call to Language::prepareTextPlaceholders() converts those brackets into HTML angle brackets, producing executable markup. This issue has been patched in version 5.0.9.

Affected products

• admidio: before 5.0.9

References

• https://github.com/Admidio/admidio/releases/tag/v5.0.9
• https://github.com/Admidio/admidio/security/advisories/GHSA-gq27-fc8w-vcmp
• https://github.com/Admidio/admidio/security/advisories/GHSA-gq27-fc8w-vcmp

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