CVE-2026-45126

Description

MyBB is free and open source forum software. Prior to 1.8.40, the Admin CP Security Questions module does not validate the anti-CSRF token correctly, allowing same-site attackers to enable or disable registration challenge questions with a specially crafted URL. The controller processes GET requests for the disable and enable actions to modify mybb_questions.active without verifying the my_post_key token attached by the user interface. The uniquely identifying implementation details include admin/modules/config/questions.php. This issue is fixed in version 1.8.40.

CVSS Vector

References

• https://github.com/mybb/mybb/commit/6893b395c7fa3b9e4de6235caea0ce198c376c4f
• https://github.com/mybb/mybb/releases/tag/mybb_1840
• https://github.com/mybb/mybb/security/advisories/GHSA-m42q-vgx3-fqcc
• https://mybb.com/versions/1.8.40