MISP up to 2.5.39 Data Structure authorization

Summaryinfo

A vulnerability has been found in MISP up to 2.5.39 and classified as critical. Affected is an unknown function of the component Data Structure Handler. This manipulation causes authorization. This vulnerability is registered as CVE-2026-54398. Remote exploitation of the attack is possible. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical was found in MISP up to 2.5.39. Affected by this vulnerability is an unknown part of the component Data Structure Handler. The manipulation with an unknown input leads to a authorization vulnerability. The CWE definition for the vulnerability is CWE-863. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

An authorization flaw in MISP’s object add/edit handling allowed an authenticated user with object editing permissions to assign a MISP object, or attributes contained within an object, to a sharing group that the user was not authorized to use or view. When editing objects, the sharing group validation was performed against the wrong request data structure after object fields had been merged to the top level, causing the check to be bypassed. In addition, attributes embedded in objects were not individually validated for authorized sharing group use. An attacker could craft a request with distribution set to 4 and an arbitrary sharing_group_id, potentially disclosing the existence or name of otherwise non-visible sharing groups and improperly modifying the distribution metadata of objects or contained attributes.

The weakness was published by Jeroen Pinoy as 4fe48c523e66999d65f99fdec9508adb3aa1c0f3. The advisory is shared at github.com. This vulnerability is known as CVE-2026-54398 since 06/12/2026. The exploitation appears to be easy. The attack can be launched remotely. Neither technical details nor an exploit are publicly available.

Upgrading to version 2.5.40 eliminates this vulnerability. Applying the patch 4fe48c523e66999d65f99fdec9508adb3aa1c0f3 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Name

• MISP

Version

• 2.5.0
• 2.5.1
• 2.5.2
• 2.5.3
• 2.5.4
• 2.5.5
• 2.5.6
• 2.5.7
• 2.5.8
• 2.5.9
• 2.5.10
• 2.5.11
• 2.5.12
• 2.5.13
• 2.5.14
• 2.5.15
• 2.5.16
• 2.5.17
• 2.5.18
• 2.5.19
• 2.5.20
• 2.5.21
• 2.5.22
• 2.5.23
• 2.5.24
• 2.5.25
• 2.5.26
• 2.5.27
• 2.5.28
• 2.5.29
• 2.5.30
• 2.5.31
• 2.5.32
• 2.5.33
• 2.5.34
• 2.5.35
• 2.5.36
• 2.5.37
• 2.5.38
• 2.5.39

License

• open-source

Website

• Product: https://github.com/MISP/MISP/

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