CVE-2026-91857
Affected versions of MISP expose several state-changing controller actions without restricting them to POST.
Overview
CVE-2026-91857 is a known-severity vulnerability. It was published on September 15, 2026.
Technical description
Affected versions of MISP expose several state-changing controller actions without restricting them to POST.
The affected actions are:
- EventReportsController::purgeUnusedPictures()
- NoticelistsController::enableNoticelist()
- ServersController::removeOrphanedCorrelations()
- WorkflowsController::rebuildRedis()
The patch adds allowMethod(['post']) to each action, preventing them from being triggered through ordinary GET requests.
For purgeUnusedPictures(), the corresponding UI previously used $.get(). The fix converts that request to POST and supplies X-CSRF-Token, while the controller enables header-only CSRF validation for that AJAX action.
Because GET requests can be induced cross-origin through links, images, redirects, or navigation, accepting GET for these state-changing operations can let an attacker trigger them using the authenticated victim's session.
Version affected: ≤2.5.45
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
References
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Frequently asked questions
What is CVE-2026-91857?
CVE-2026-91857 is a known-severity vulnerability. It was published on September 15, 2026.
How severe is CVE-2026-91857?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2026-91857?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-91857?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-91857 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.