CVE-2026-91819: MISP: HTTP Method Override Bypasses CSRF and Form Validation in BetterSecurityComponent
Affected versions of MISP rely on CakePHP request-method override processing in a way that can disable CSRF and form-security validation.
CakePHP honors a method field or X-HTTP-Method-Override header by rewriting the effective request method. For override values outside the normal write verbs POST, PUT, PATCH, and DELETE, CakePHP also clears the parsed request body. MISP’s security component then determines whether to perform validatePost() and validateCsrf() based on whether request data remains. With a value such as:
method=GET
the body becomes empty before those checks run, so both protections are skipped. A cross-site form containing only that override can therefore reach actions whose parameters are taken from the URL rather than the request body
Version affected: ≤2.5.45
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
MISP (BetterSecurityComponent fix)to a version that resolves this vulnerability.Fixed in ≤2.5.45
Event History
Frequently Asked Questions
What does an attacker need to exploit this issue?
An attacker needs to cause a victim’s browser to submit a cross-site form containing an invalid method override, such as _method=GET. Exploitation is limited to reachable actions that obtain their parameters from the URL rather than the request body.
Are default CSRF and form-security protections sufficient?
No. The affected request-method override handling can empty the parsed request body before MISP decides whether to run CSRF and form-security validation, causing both checks to be skipped.
Which MISP versions are affected?
MISP versions 2.5.45 and earlier are affected.
How can I reduce exposure before updating?
Prevent untrusted cross-site requests from reaching MISP where possible, since the attack relies on a victim browser submitting a form. Pay particular attention to URL-parameterized actions, because those are identified as reachable after the request body is cleared.