Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to enforce run-state validation on write operations for finished playbook runs which… (CVE-2026-16046)
Mattermost versions 11.7.x up to 11.7.6 and 10.11.x up to 10.11.21 contain a vulnerability where run-state validation is not enforced on write operations for finished playbook runs. This flaw allows participants of a run to modify certain aspects such as status, checklists, retrospective content, ownership, and participants on completed runs via REST and GraphQL API requests.
AI Analysis
Technical Summary
The vulnerability identified as CVE-2026-16046 affects Mattermost versions 11.7.x up to 11.7.6 and 10.11.x up to 10.11.21. It arises from the failure to enforce run-state validation on write operations targeting finished playbook runs. As a result, a participant in a run can modify the run's status, checklists, retrospective content, ownership, and participants even after the run is completed, through REST and GraphQL API calls. This is a form of improper authorization (CWE-863). The CVSS v3.1 base score is 4.3, indicating a medium severity vulnerability with network attack vector, low attack complexity, requiring low privileges, no user interaction, unchanged scope, no confidentiality or availability impact, but with integrity impact.
Potential Impact
An attacker with participant privileges in a Mattermost playbook run can alter the state and content of completed runs, potentially undermining the integrity of playbook records. This could affect audit trails, accountability, and the accuracy of retrospective analyses. There is no direct confidentiality or availability impact reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory (Mattermost Advisory ID: MMSA-2026-00675) for current remediation guidance. Until a patch or official fix is available, restrict participant privileges where possible to limit unauthorized modifications to finished playbook runs.
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to enforce run-state validation on write operations for finished playbook runs which… (CVE-2026-16046)
Description
Mattermost versions 11.7.x up to 11.7.6 and 10.11.x up to 10.11.21 contain a vulnerability where run-state validation is not enforced on write operations for finished playbook runs. This flaw allows participants of a run to modify certain aspects such as status, checklists, retrospective content, ownership, and participants on completed runs via REST and GraphQL API requests.
CVSS v3.1
Score 4.3medium
Affected software
pkg:github/mattermost/mattermost-serverRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability identified as CVE-2026-16046 affects Mattermost versions 11.7.x up to 11.7.6 and 10.11.x up to 10.11.21. It arises from the failure to enforce run-state validation on write operations targeting finished playbook runs. As a result, a participant in a run can modify the run's status, checklists, retrospective content, ownership, and participants even after the run is completed, through REST and GraphQL API calls. This is a form of improper authorization (CWE-863). The CVSS v3.1 base score is 4.3, indicating a medium severity vulnerability with network attack vector, low attack complexity, requiring low privileges, no user interaction, unchanged scope, no confidentiality or availability impact, but with integrity impact.
Potential Impact
An attacker with participant privileges in a Mattermost playbook run can alter the state and content of completed runs, potentially undermining the integrity of playbook records. This could affect audit trails, accountability, and the accuracy of retrospective analyses. There is no direct confidentiality or availability impact reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory (Mattermost Advisory ID: MMSA-2026-00675) for current remediation guidance. Until a patch or official fix is available, restrict participant privileges where possible to limit unauthorized modifications to finished playbook runs.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-2883-3c4j-4mvv
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-16046"]
- Ecosystems
- []
- Database Specific Severity
- MODERATE
- Cvss Version
- 3.1
Threat ID: 6a833347bf8831d5392a3e37
Added to database: 08/17/2026, 16:13:59 UTC
Last enriched: 08/17/2026, 16:17:48 UTC
Last updated: 08/17/2026, 18:41:22 UTC
Views: 3
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