CVE-2026-103239

MISP Tag Collection Save Allows Privilege Escalation via Sibling Model Injection

Published Sep 30, 2026 CVSS 4.0 · 8.6 High EPSS < 1% KEV · Not listed
Description
MISP contains a privilege escalation vulnerability in the tag collection creation and editing functionality. The affected actions accepted the full HTTP request payload and passed it to a bulk-association save operation, which writes not only the intended tag collection record but also any associated model data present in the payload.

A user holding the tag editor permission could craft a request that includes additional model data (such as User or Organisation records) alongside the tag collection fields. Because the save operation processed all associated models indiscriminately, the injected sibling records were written to the database, enabling the attacker to modify or create privileged accounts and escalate to site administrator.

Preconditions:

- An authenticated account with the tag editor permission (perm_tag_editor)

- Network access to the MISP instance

Impact:

- Unauthorized creation or modification of User and Organisation records

- Privilege escalation from tag editor to site administrator

Affected versions: < 2.5.48

Remediation

Vendor Solution

The fix replaces the bulk-association save call with an explicit two-step process: first, only the TagCollection data is extracted from the request and saved via a plain save() operation that does not write belongsTo siblings; second, tag association rows are persisted individually in a controlled loop. This ensures that any User, Organisation, or other sibling model data present in the request payload is silently discarded and never reaches the database, eliminating the privilege escalation path.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

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

Type Values Removed Values Added
Description MISP contains a privilege escalation vulnerability in the tag collection creation and editing functionality. The affected actions accepted the full HTTP request payload and passed it to a bulk-association save operation, which writes not only the intended tag collection record but also any associated model data present in the payload. A user holding the tag editor permission could craft a request that includes additional model data (such as User or Organisation records) alongside the tag collection fields. Because the save operation processed all associated models indiscriminately, the injected sibling records were written to the database, enabling the attacker to modify or create privileged accounts and escalate to site administrator. Preconditions: - An authenticated account with the tag editor permission (perm_tag_editor) - Network access to the MISP instance Impact: - Unauthorized creation or modification of User and Organisation records - Privilege escalation from tag editor to site administrator Affected versions: < 2.5.48
Title MISP Tag Collection Save Allows Privilege Escalation via Sibling Model Injection
First Time appeared Misp
Misp misp
Weaknesses CWE-284
CWE-862
CPEs cpe:2.3:a:misp:misp:*:*:*:*:*:*:*:*
Vendors & Products Misp
Misp misp
References
Metrics cvssV4_0

{'score': 8.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
CIRCL
Published
Updated
Sep 30, 2026, 4:50 PM
Reserved
Sep 30, 2026, 10:16 AM
Status
Deferred
Published
Sep 30, 2026, 11:16 AM
Modified
Sep 30, 2026, 5:16 PM