CVE-2026-95671

MISP Collections: Missing Authorization Check for Sharing Group on PUT Request in collections/add

Published Sep 22, 2026 CVSS 4.0 · 5.3 Medium EPSS < 1% KEV · Not listed
Description
In MISP, the CollectionsController add() method enforced the sharing-group usability authorization check and element capture only when the HTTP request method was POST. However, the underlying CRUDComponent::add() method persists data on both POST and PUT requests. As a result, an authenticated user could issue a PUT request to the collections/add endpoint, bypassing the sharing-group authorization check entirely. This allowed the creation of a collection with distribution=4 (shared with a specific sharing group) targeting a sharing group that the user was not authorized to use. The bypassed check would normally verify that the current user has access to the specified sharing group before allowing the collection to be associated with it.

The security impact is that an authenticated user can place collection data into a sharing group context they do not have legitimate access to, potentially exposing that data to all members of the unauthorized sharing group and violating the intended access-control boundaries of the MISP instance.

The vulnerability requires an authenticated session and knowledge of a valid sharing group identifier; no user interaction or special tooling is needed beyond sending a PUT request instead of a POST request to the same endpoint.

Remediation

Vendor Solution

The authorization guard in CollectionsController::add() was extended to cover PUT requests in addition to POST requests. The sharing-group usability check (which validates that the current user can use the target sharing group) and the element capture logic now execute regardless of whether the request arrives as POST or PUT, ensuring that CRUDComponent::add() cannot persist a collection with an unauthorized sharing group via either HTTP verb.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Misp
Misp misp
Vendors & Products Misp
Misp misp
Type Values Removed Values Added
Description In MISP, the CollectionsController add() method enforced the sharing-group usability authorization check and element capture only when the HTTP request method was POST. However, the underlying CRUDComponent::add() method persists data on both POST and PUT requests. As a result, an authenticated user could issue a PUT request to the collections/add endpoint, bypassing the sharing-group authorization check entirely. This allowed the creation of a collection with distribution=4 (shared with a specific sharing group) targeting a sharing group that the user was not authorized to use. The bypassed check would normally verify that the current user has access to the specified sharing group before allowing the collection to be associated with it. The security impact is that an authenticated user can place collection data into a sharing group context they do not have legitimate access to, potentially exposing that data to all members of the unauthorized sharing group and violating the intended access-control boundaries of the MISP instance. The vulnerability requires an authenticated session and knowledge of a valid sharing group identifier; no user interaction or special tooling is needed beyond sending a PUT request instead of a POST request to the same endpoint.
Title MISP Collections: Missing Authorization Check for Sharing Group on PUT Request in collections/add
Weaknesses CWE-285
CWE-862
References
Metrics cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
CIRCL
Published
Updated
Sep 22, 2026, 3:32 PM
Reserved
Sep 22, 2026, 1:20 PM
Status
Deferred
Published
Sep 22, 2026, 2:17 PM
Modified
Sep 22, 2026, 4:18 PM