Medium severity · published Jun 25, 2026
CVE-2026-2299
Improper Access Control in Mattermost Google Drive Plugin File Creation Endpoint
4.3
CVSS
0.2%
EPSS
No
On KEV
Description
The Mattermost Google Drive plugin before version 1.1.0 fails to validate channel membership in the file creation endpoint, allowing authenticated users with a connected Google account to share Google Drive files to unauthorized private channels and disclose private channel membership.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 10% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MG
Mattermost Google Drive Plugin · Mattermost
through 1.0.0 · source: vendor
GD
Google Drive · Mattermost
before 1.1.0; 1.1.0; 1.1.0 · source: NVD