CVE-2026-85538 MISP Attribute Deletion Authorization Bypass Allows Users Without Modify Permissions to Delete Attributes
Authenticated users can delete event attributes without proper modification permissions, leading to unauthorized data loss in MISP threat intelligence platforms.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-85538?
CVE-2026-85538 is a high-severity missing authorization vulnerability in misp, published on 4 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
An incorrect authorization vulnerability in MISP allowed authenticated users to delete attributes from events despite lacking the required perm_modify or perm_modify_org permissions.
The affected attribute deletion paths relied on organization membership checks performed by MispAttribute::deleteAttribute() but did not consistently enforce MISP's event modification authorization rules. Consequently, a user belonging to the organization associated with an event could potentially delete individual attributes or perform bulk attribute deletion even when their assigned role was not authorized to modify the event.
This created an inconsistency between attribute editing and deletion: editing an attribute correctly used MISP's ACL::canModifyEvent() authorization logic, whereas the affected deletion operations could bypass these permission checks.
An authenticated attacker with access to an affected MISP instance and membership in the organization owning an event could exploit this flaw to remove attributes from that event, potentially causing unauthorized modification or loss of threat intelligence data.
The patch introduces a common authorization check for all affected deletion paths. Before deletion, MISP now resolves the associated events and verifies that the current user is authorized to modify each event using the same authorization mechanism used by normal event and attribute modification operations.
Weakness: CWE-863
Which versions are affected by CVE-2026-85538?
How do I fix CVE-2026-85538?
No fix has been published for CVE-2026-85538 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-85538 being exploited?
There is no known exploitation of CVE-2026-85538 in the wild and no public exploit code.
Sources
Also known as GHSA-9pvc-hwg3-vhmw.