CVE-2026-91819 MISP: HTTP Method Override Bypasses CSRF and Form Validation in BetterSecurityComponent
Attackers can bypass CSRF and form validation in MISP by using HTTP method overrides, allowing unauthorized actions via crafted cross-site requests.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-91819?
CVE-2026-91819 is a medium-severity vulnerability in MISP, published on 15 Sep 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
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
Which versions are affected by CVE-2026-91819?
How do I fix CVE-2026-91819?
No fix has been published for CVE-2026-91819 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-91819 being exploited?
There is no known exploitation of CVE-2026-91819 in the wild and no public exploit code.
Sources
Also known as GHSA-fx6r-c922-6mvg.