Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to prevent guest users from receiving Board Admin privileges during board archive… (CVE-2026-16044)
Mattermost versions 11.7.x up to 11.7.6 and 10.11.x up to 10.11.21 contain a vulnerability that allows guest users to be escalated to Board Admin privileges during the import of a crafted board archive file. This privilege escalation occurs because the software fails to properly restrict guest user permissions in this context. The issue is identified as CVE-2026-16044 and has a medium severity rating with a CVSS score of 5.4.
AI Analysis
Technical Summary
CVE-2026-16044 affects Mattermost versions 11.7.x (up to 11.7.6) and 10.11.x (up to 10.11.21). The vulnerability arises from improper permission checks during the import of a board archive file (.boardarchive), which allows a board member to escalate a guest user to Board Admin privileges. This is a privilege escalation vulnerability categorized under CWE-863 (Incorrect Authorization). No patch or official fix information is provided in the available data. The vulnerability has a CVSS v3.1 score of 5.4, indicating moderate impact with network attack vector, low attack complexity, and requiring low privileges but no user interaction.
Potential Impact
The vulnerability allows an attacker with board member privileges to escalate a guest user to Board Admin during board archive import. This could lead to unauthorized administrative control over board functions, potentially impacting integrity and availability of board data. There is no indication of confidentiality impact. No known exploits in the wild have been reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory (Mattermost Advisory ID: MMSA-2026-00672) for current remediation guidance. Until an official fix is available, restrict board archive imports to trusted users only and monitor for suspicious privilege escalations related to guest accounts.
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 fail to prevent guest users from receiving Board Admin privileges during board archive… (CVE-2026-16044)
Description
Mattermost versions 11.7.x up to 11.7.6 and 10.11.x up to 10.11.21 contain a vulnerability that allows guest users to be escalated to Board Admin privileges during the import of a crafted board archive file. This privilege escalation occurs because the software fails to properly restrict guest user permissions in this context. The issue is identified as CVE-2026-16044 and has a medium severity rating with a CVSS score of 5.4.
CVSS v3.1
Score 5.4medium
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
CVE-2026-16044 affects Mattermost versions 11.7.x (up to 11.7.6) and 10.11.x (up to 10.11.21). The vulnerability arises from improper permission checks during the import of a board archive file (.boardarchive), which allows a board member to escalate a guest user to Board Admin privileges. This is a privilege escalation vulnerability categorized under CWE-863 (Incorrect Authorization). No patch or official fix information is provided in the available data. The vulnerability has a CVSS v3.1 score of 5.4, indicating moderate impact with network attack vector, low attack complexity, and requiring low privileges but no user interaction.
Potential Impact
The vulnerability allows an attacker with board member privileges to escalate a guest user to Board Admin during board archive import. This could lead to unauthorized administrative control over board functions, potentially impacting integrity and availability of board data. There is no indication of confidentiality impact. No known exploits in the wild have been reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory (Mattermost Advisory ID: MMSA-2026-00672) for current remediation guidance. Until an official fix is available, restrict board archive imports to trusted users only and monitor for suspicious privilege escalations related to guest accounts.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-496c-r634-6cgj
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-16044"]
- Ecosystems
- []
- Database Specific Severity
- MODERATE
- Cvss Version
- 3.1
Threat ID: 6a833345bf8831d5392a3c7d
Added to database: 08/17/2026, 16:13:57 UTC
Last enriched: 08/17/2026, 16:17:24 UTC
Last updated: 08/17/2026, 19:01:08 UTC
Views: 4
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