MISP Tag Collection Save Allows Privilege Escalation via Sibling Model Injection (CVE-2026-103239) | HOL Guard CVE

High · CVSS 8.6CVE-2026-103239

MISP Tag Collection Save Allows Privilege Escalation via Sibling Model Injection

Answer in brief

CVE-2026-103239 records a High severity (CVSS 8.6) vulnerability in MISP Tag Collection Save Allows Privilege Escalation via Sibling Model Injection. The current sources do not mark it as known exploited. The current feed maps MISP/MISP (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 30, 2026Updated Sep 30, 2026Source checked Sep 30, 2026First seen by HOL Sep 30, 2026Material review Sep 30, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.6
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps MISP/MISP (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
MISP/MISPgeneric	>=0 <2.5.48	2.5.48

Recommended response

Check inventory. Check lockfiles and deployed manifests for MISP/MISP.
Review the reported fix. Source-reported 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.

Evidence timeline and material changes

Published upstream
Sep 30, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 30, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 30, 2026

Sources and claim methodology

GitHub security advisorygithub.com

Upstream source 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

Quoted source text, attributed separately from HOL analysis.