CVE-2026-85236MISP cullEmptyEvents CSRF Allows Irreversible Deletion of Events via GET Request

Official description

A cross-site request forgery (CSRF) vulnerability existed in the cullEmptyEvents action of MISP. The endpoint performed a state-changing and irreversible operation while accepting HTTP GET requests. Because bodyless GET requests are not subject to CakePHP's CSRF validation, an attacker could cause an authenticated MISP user with sufficient privileges to invoke the endpoint simply by causing their browser to load a crafted URL, for example through an embedded image or other automatically requested resource. Successful exploitation triggers the deletion of published empty events. The deletion is particularly significant because the operation uses skipBlocklist, meaning the removed events do not leave blocklist entries that could prevent or track their subsequent synchronization. This can result in unintended and potentially irreversible deletion of MISP event records without explicit user interaction. The vulnerability was addressed by restricting cullEmptyEvents to HTTP POST requests, ensuring that CakePHP's normal CSRF protections are applied to the operation.

Affected products (as reported)

References

• https://github.com/MISP/MISP/commit/2b6b3ac90 patch
• https://github.com/MISP/MISP/commit/50106c9a0 patch
• https://github.com/MISP/MISP/commit/66ecb5acb patch
• https://github.com/MISP/MISP/commit/9c1346ce1 patch
• https://github.com/MISP/MISP/commit/cfc8b8a6d patch