CVE-2026-10855
Undergoing Analysis Undergoing Analysis - In Progress
Authorization Bypass in MISP Event Template Importer

Publication date: 2026-06-04

Last updated on: 2026-06-04

Assigner: 5a6e4751-2f3f-4070-9419-94fb35b644e8

Description
An authorization flaw existed in the MISP Event Template Importer overwrite workflow. When importing an event template in overwrite mode, the application checked whether a matching template already existed but did not verify that the importing user belonged to the organization that owned the existing template. As a result, an authenticated user with access to the template import functionality could forcibly overwrite an event template owned by another organization. Successful exploitation could allow unauthorized modification of another organization’s event template, potentially altering template structure, attributes, or metadata used for subsequent event creation or sharing workflows. Site administrators are not affected by this restriction, as they are explicitly allowed to overwrite templates across organizations. The issue was fixed by enforcing an ownership check before overwrite: non-site-admin users may only overwrite templates owned by their own organization.
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Meta Information
Published
2026-06-04
Last Modified
2026-06-04
Generated
2026-06-04
AI Q&A
2026-06-04
EPSS Evaluated
N/A
NVD
EUVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
misp misp to 7c2200d143bef86aaf58d701b6968a843097db69 (inc)
Helpful Resources
Exploitability
CWE
CWE Icon
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.
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AI Powered Q&A
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:

This vulnerability allows an authenticated user to overwrite event templates owned by other organizations without proper authorization. Such unauthorized modification of data could lead to integrity and confidentiality issues within the affected system.

While the provided information does not explicitly mention compliance with standards like GDPR or HIPAA, unauthorized data modification and lack of proper access controls can potentially violate requirements related to data integrity, access control, and accountability found in these regulations.

The fix enforces ownership checks before allowing template overwrites, which helps restore proper access control and reduces the risk of unauthorized data changes, thereby supporting compliance efforts.


Can you explain this vulnerability to me?

This vulnerability is an authorization flaw in the MISP Event Template Importer overwrite workflow. When a user imports an event template in overwrite mode, the system checked if a matching template existed but did not verify if the user belonged to the organization that owned the existing template.

As a result, an authenticated user with access to the template import functionality could overwrite an event template owned by another organization without proper authorization.

Site administrators are exempt from this restriction and can overwrite templates across organizations. The issue was fixed by adding an ownership check that restricts non-site-admin users to only overwrite templates owned by their own organization.


How can this vulnerability impact me? :

Successful exploitation of this vulnerability allows an unauthorized user to modify another organization's event template.

This could lead to changes in the template structure, attributes, or metadata that are used in subsequent event creation or sharing workflows, potentially causing misinformation, data integrity issues, or disruption in collaborative processes.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

Detection of this vulnerability involves monitoring attempts to overwrite event templates owned by other organizations without proper authorization.

Specifically, you should look for error messages or logs indicating failed overwrite attempts with messages such as "Cannot overwrite template owned by another org."

Commands or methods to detect this might include reviewing application logs for such error messages or monitoring API calls related to event template imports in overwrite mode.

Since the vulnerability is related to authorization checks during template overwrite, checking audit logs for unexpected template modifications by users outside the owning organization can also help detect exploitation attempts.


What immediate steps should I take to mitigate this vulnerability?

To mitigate this vulnerability immediately, ensure that your MISP instance is updated with the patch that enforces ownership checks before allowing template overwrites.

The fix requires that non-site-admin users can only overwrite templates owned by their own organization, blocking unauthorized overwrite attempts.

If updating immediately is not possible, restrict access to the template import overwrite functionality to trusted users or site administrators only.

Additionally, monitor and audit template overwrite activities to detect any unauthorized attempts.


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