Flarum's Logout Route allows open redirects

CVE-2024-21641

What is CVE-2024-21641?

Flarum, an open-source discussion platform, was found to have a vulnerability related to its /logout route prior to version 1.8.5. The issue lies in a redirect parameter that can be manipulated by third parties, enabling unauthorized redirects of users from a trusted Flarum domain to potentially harmful links. While logged-in users must confirm their logout, guests are redirected immediately. This behavior can be exploited by spammers and malicious actors to leverage the trusted domain of a Flarum installation. Users are encouraged to update to flarum/core v1.8.5, where the vulnerability has been addressed. Additionally, certain extensions that modify the logout route may offer temporary workarounds if implemented securely.

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