CVE-2026-41661 — Cross-Site Scripting (XSS)

title: Admidio Reflected XSS via msg_window.php - CVE-2026-41661
id: scw-2026-05-07-ai-1
status: experimental
level: medium
description: |
  Detects attempts to exploit CVE-2026-41661 in Admidio. The rule looks for requests to '/system/msg_window.php' containing URL parameters that are likely used in the exploit, specifically looking for encoded square brackets '%5B%5D' which are then processed by the vulnerable application logic.
author: SCW Feed Engine (AI-generated)
date: 2026-05-07
references:
  - https://shimiscyberworld.com/posts/nvd-CVE-2026-41661/
tags:
  - attack.initial_access
  - attack.t1190
logsource:
    category: webserver
detection:
  selection:
      cs-uri|contains:
          - '/system/msg_window.php'
      cs-uri-query|contains:
          - 'msg=' 
          - 'user='
      cs-uri-query|contains:
          - '%5B%5D'
      condition: selection
falsepositives:
  - Legitimate administrative activity

Source: Shimi's Cyber World · License & reuse