CVE-2026-56423
CRITICAL 9.4MISP Core contained broken access-control checks in the bulk deletion flows for Event Reports and Sharing Groups. The affected deleteSelection handlers authorized deletion using broad role-level permissions instead of validating authorization for each selected object. For Event Reports, EventReportsController::deleteSelection relied on the global perm_add capability rather than a per-report ownership/authorization check. As a result, a contributor-level user could submit report IDs or UUIDs for reports belonging to other organisations and hard-delete them instance-wide. The fix changed the callback to call EventReport::fetchIfAuthorized($user, $itemId, 'delete') for each selected report before deletion. For Sharing Groups, SharingGroupsController::deleteSelection relied on the global perm_sharing_group capability rather than verifying ownership of each selected sharing group. This allowed a sharing-group-capable user to hard-delete sharing groups owned by other organisations, bypassing the per-object ownership gate used by the single-object delete action. The fix changed the callback to call SharingGroup::checkIfOwner($user, $itemId) for each selected sharing group. An authenticated attacker with the relevant broad role permission could abuse the affected bulk deletion endpoints to delete objects outside their organisation’s authorization scope, causing loss of event-report content or sharing-group configuration across the instance.
Severe if exploited (CVSS 9.4), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 17th percentile
Impact if exploited
9.4CVSS 4.0 · CRITICAL
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ⚠Privileges: Requires a low-privilege account
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
- ✓Requirements: No special attack requirements
✓ lowers the bar for an attacker · ⚠ raises it
Weakness (CWE)
- CWE-862: Missing authorization
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H