CVE-2026-9708
Published:July 13, 2026
Updated:July 21, 2026
Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to validate that an assigned incoming webhook user has access to the target team or channel, which allows a requester with webhook management permissions to create posts or direct messages attributed to another user via crafted incoming webhook configuration and payloads.. Mattermost Advisory ID: MMSA-2026-00683
Affected Packages
https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v11.6.0 <v11.6.5Fix Suggestion:
Update to version v11.6.5https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v10.11.0 <v10.11.20Fix Suggestion:
Update to version v10.11.20https://github.com/mattermost/mattermost.git (GITHUB):
Affected version(s) >=v11.7.0 <v11.7.3Fix Suggestion:
Update to version v11.7.3github.com/mattermost/mattermost (GO):
Affected version(s) >=v10.11.0 <v10.11.20Fix Suggestion:
Update to version v10.11.20github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.7.0 <v11.7.3Fix Suggestion:
Update to version v11.7.3github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.6.0 <v11.6.5Fix Suggestion:
Update to version v11.6.5Related Resources (1)
Do you need more information?
Contact UsCVSS v4
Base Score:
6.9
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
HIGH
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
4.9
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Authorization Bypass Through User-Controlled Key
EPSS
Base Score:
0.21