CVE-2026-91846
Received Received - Intake

Unauthorized Collection Element Creation in MISP

Vulnerability report for CVE-2026-91846, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-09-15

Last updated on: 2026-09-15

Assigner: CIRCL

Description

Affected versions of MISP allow a collection element to be created from a bare UUID without consistently checking whether the acting user is allowed to access the referenced object. The commit explains that collection elements themselves only store UUIDs, while the collection view later resolves those UUIDs into their underlying objects. Before this fix, the generic add() path could therefore persist a UUID for an Event or Galaxy Cluster that the caller could not normally read. The patch explicitly notes that this made collections a way to reference another organisation’s private data and had caused disclosure of organisation-only events in the beta collection view. The fix centralizes authorization in __assertCanUseElements(). Event UUIDs are validated through Event::fetchSimpleEvent() under the current user’s ACL, while Galaxy Cluster UUIDs are checked through GalaxyCluster::fetchGalaxyClusters(). The check is applied both to the CRUD add() path and to addElementToCollection(). Version affected: ≀2.5.45

CVSS Scores

EPSS Scores

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Meta Information

Published
2026-09-15
Last Modified
2026-09-15
Generated
2026-09-15
AI Q&A
2026-09-15
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
misp misp to 2.5.45 (inc)
misp misp to 2.5.45 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-862 The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
CWE-639 The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

Attack-Flow Graph

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Executive Summary

This vulnerability in MISP allows users to create collection elements using a UUID without verifying if they have permission to access the referenced object. Collection elements store UUIDs, which are later resolved into objects during viewing. Before the fix, this allowed unauthorized access to private data by referencing objects the user could not normally read.

Impact Analysis

This vulnerability could lead to unauthorized disclosure of private data, such as organization-only events or restricted galaxy clusters. Attackers could exploit it to access sensitive information they are not permitted to view by adding restricted UUIDs to their collections.

Compliance Impact

This vulnerability could violate compliance requirements by enabling unauthorized access to sensitive data, such as personal or health information. GDPR and HIPAA require strict access controls and protection of personal data, which this flaw undermines by allowing data leaks.

Mitigation Strategies

Upgrade MISP to version 2.5.46 or later to apply the authorization fix in __assertCanUseElements(). Review collection elements for unauthorized references to private events or galaxy clusters. Restrict access to sensitive data until the upgrade is complete.

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