CVE-2026-91819

MISP: HTTP Method Override Bypasses CSRF and Form Validation in BetterSecurityComponent

Published Sep 15, 2026 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed
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

Remediation

Vendor Solution

The fix introduces a __rejectUnsafeMethodOverride() check in BetterSecurityComponent::startup() that executes before the parent SecurityComponent::startup() computes $hasData. It inspects both the _method POST field and the X-HTTP-Method-Override header (mirroring CakePHP's precedence) and rejects any value that is not a string in the allowed set {POST, PUT, PATCH, DELETE}. Non-string values (e.g., array payloads like _method[]=GET) are also refused. A BadRequestException is thrown and the event is logged, preventing the request from ever reaching the parent security logic with an emptied body.

Tracking

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Advisories

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History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Misp
Misp misp
Vendors & Products Misp
Misp misp
Type Values Removed Values Added
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
Title MISP: HTTP Method Override Bypasses CSRF and Form Validation in BetterSecurityComponent
Weaknesses CWE-20
CWE-352
References
Metrics cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
CIRCL
Published
Updated
Sep 15, 2026, 2:37 PM
Reserved
Sep 15, 2026, 7:41 AM
Status
Deferred
Published
Sep 15, 2026, 8:17 AM
Modified
Sep 16, 2026, 1:42 PM