CVE-2026-104910

Overview

MISP suffers an authorization bypass in its related events listing, allowing users to retrieve metadata of events they should not see. This can expose threat‑intelligence details across sharing groups.

Description

MISP contains an authorization bypass in the related events listing functionality. When a user requests the list of events correlated to a given event, the system retrieved related event metadata directly from the correlation table without re-validating the caller's access rights against each related event. The correlation table stores a snapshot of the event's distribution level and sharing group at the time the correlation was created, and does not carry the published flag. As a result, events that the caller is not permitted to open—because they are unpublished, or because their distribution or sharing group has changed since the correlation was recorded—were still returned with their metadata (title, date, correlating value counts). Preconditions: - An authenticated user with access to at least one event in MISP. - The existence of correlation entries linking that event to other events the user should not be able to view. Impact: - Unauthorized disclosure of event metadata (titles, dates, correlation counts) for events the user has no right to access. - Potential reconnaissance of threat-intelligence event names and timelines across sharing groups. Affected: MISP versions prior to the fix commit (2ffa97f05).

Impact

Confidentiality is compromised as unauthorized users can view event titles, dates, and correlation counts. Integrity is not directly affected. Availability remains unchanged. The impact is on organizations using MISP to share threat intelligence, potentially exposing sensitive event metadata.

Remediation

Apply the security fix from commit 2ffa97f05 or upgrade to the latest MISP release. If upgrade is not possible, restrict API access to the related events endpoint or enforce ACL checks on event metadata retrieval. Monitor logs for anomalous access patterns.

Risk context

The vulnerability has a medium severity rating (CVSS v3 4.3, v4 5.3) and no EPSS score, indicating moderate risk. Organizations should assess exposure based on their MISP deployment and user permissions.

Affected products

• MISP