CVE-2026-2299: CWE-862: Missing Authorization in Mattermost Mattermost Google Drive Plugin
CVE-2026-2299 is a medium severity vulnerability in the Mattermost Google Drive plugin versions 1.0.0 and earlier. The plugin fails to validate channel membership on the file creation endpoint, allowing authenticated users with connected Google accounts to share Google Drive files to private channels they are not authorized to access. This can lead to unauthorized disclosure of private channel membership information.
AI Analysis
Technical Summary
The Mattermost Google Drive plugin before version 1.1.0 contains a missing authorization vulnerability (CWE-862) where the file creation endpoint does not properly verify if the user is a member of the target channel. As a result, authenticated users with a connected Google account can share files to private channels without membership, potentially exposing private channel membership details. The vulnerability affects versions up to and including 1.0.0. There is no vendor-provided remediation level or patch information available at this time.
Potential Impact
An attacker who is an authenticated Mattermost user with a connected Google account can share Google Drive files to private channels they do not belong to. This leads to unauthorized disclosure of private channel membership information and partial confidentiality loss. The CVSS score is 4.2 (medium), reflecting low impact on confidentiality and integrity, and no impact on availability.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict plugin usage to trusted users and monitor sharing activities involving private channels to detect potential misuse.
CVE-2026-2299: CWE-862: Missing Authorization in Mattermost Mattermost Google Drive Plugin
Description
CVE-2026-2299 is a medium severity vulnerability in the Mattermost Google Drive plugin versions 1.0.0 and earlier. The plugin fails to validate channel membership on the file creation endpoint, allowing authenticated users with connected Google accounts to share Google Drive files to private channels they are not authorized to access. This can lead to unauthorized disclosure of private channel membership information.
CVSS v3.1
Score 4.2medium
Affected software
pkg:github/Mattermost Google Drive PluginRun 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 Mattermost Google Drive plugin before version 1.1.0 contains a missing authorization vulnerability (CWE-862) where the file creation endpoint does not properly verify if the user is a member of the target channel. As a result, authenticated users with a connected Google account can share files to private channels without membership, potentially exposing private channel membership details. The vulnerability affects versions up to and including 1.0.0. There is no vendor-provided remediation level or patch information available at this time.
Potential Impact
An attacker who is an authenticated Mattermost user with a connected Google account can share Google Drive files to private channels they do not belong to. This leads to unauthorized disclosure of private channel membership information and partial confidentiality loss. The CVSS score is 4.2 (medium), reflecting low impact on confidentiality and integrity, and no impact on availability.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict plugin usage to trusted users and monitor sharing activities involving private channels to detect potential misuse.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Mattermost
- Date Reserved
- 2026-02-10T16:46:56.322Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a3d89044853345fc1651099
Added to database: 06/25/2026, 20:01:08 UTC
Last enriched: 06/25/2026, 20:10:33 UTC
Last updated: 06/26/2026, 00:52:07 UTC
Views: 20
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