Executive brief
REDAXO is a PHP-based content management system. An authenticated admin can be tricked via a malicious webpage into silently updating add-ons to attacker-controlled versions without their knowledge. This could allow remote code execution if combined with a compromised add-on or a known vulnerable version, or be used to disrupt site operations through forced unwanted updates.
Technical details
The `rex_api_install_package_update` API function in REDAXO's install addon fails to override the `requiresCsrfProtection()` method, which defaults to `false` in the base `rex_api_function` class. An attacker can craft a CSRF attack (e.g., via an image tag on a malicious page) to trigger package updates when an authenticated admin visits the page. No user interaction beyond visiting the attacker's page is required, only that the admin remains logged into their REDAXO instance. The attack can force installation of specific add-on versions, creating a remote code execution vector if the targeted version contains vulnerabilities or has been compromised. The fix is straightforward: override `requiresCsrfProtection()` to return `true` in the vulnerable class, as other similar API functions already do.
Affected products
- REDAXO REDAXO
Timeline
- 2026-09-23: disclosed