CVE-2026-95671MISP Collections: Missing Authorization Check for Sharing Group on PUT Request in collections/add

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.

Timeline

Scores

EPSS (exploitation in 30 days)

0.37% · top 68% of all CVEs (13 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.

Affected products

• MISP · MISP

  • affected < 2.5.47

What to do

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.

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-84380 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-95671](https://cveledger.app/badge/CVE-2026-95671.svg)](https://cveledger.app/cve/CVE-2026-95671)

Record last updated 22 Sept 2026, 15:32 UTC.