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CVE-2026-41661

Admidio: Reflected XSS in msg_window.php via Square Bracket to HTML Tag Conversion

Published: May 7, 2026Updated: May 7, 2026 Sources: CVE List NVDCWE-79
NVD MITRE
6.1CVSSMEDIUM
EPSS Score
0.2%
Top 92.3%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:RS:CC:LI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:CScope
Changed
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-79

Affected Products

admidioAdmidio
On-prem
Enterprise Software / collaboration-groupware
admidiooss-projectEnterprise Softwareaka admidio/admidio

Attack Graph

Products CVE Techniques Tactics

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Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

2 techniques
Execution
Initial Access
View detailed technique mapping

References

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

Timeline

Published
May 7, 2026
Last Updated
May 7, 2026

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