Executive brief
MISP, an open-source threat intelligence platform, contains a flaw in its login function that allows attackers to bypass brute-force protection and multi-factor authentication by using non-standard HTTP methods. An unauthenticated attacker could exploit this to make unlimited login attempts without rate-limiting or two-factor authentication verification, potentially gaining unauthorized access to the system and its sensitive threat intelligence data.
Technical details
The UsersController.php login() function uses an allowlist approach to validate HTTP methods, checking only for POST and PUT before enforcing brute-force blocklisting, OTP verification, and login-failure logging. An attacker can circumvent all three security controls by sending login requests with alternative HTTP methods (GET, DELETE, etc.), bypassing rate-limiting, 2FA, and audit trails. A patch adjusting the HTTP method validation has been published in commit ef4dc19.
Affected products
- MISP MISP before 2.5.47
Timeline
- 2026-09-21: disclosed