CVE-2026-93851
Published:October 28, 2026
Updated:November 01, 2026
Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10 fail to validate the target post ID in the Agents plugin's mention reminder component, which allows an authenticated user who can post in a channel visible to a system administrator to cause the administrator's browser to send an unintended API request, resulting in replacement of an installed plugin and code execution on the server, via a crafted post containing a forged mention reminder that the administrator clicks. Mattermost Advisory ID: MMSA-2026-00742
Affected Packages
https://github.com/mattermost/mattermost-plugin-agents.git (GITHUB):
Affected version(s) >=v2.5.0-rc1 <v2.5.0Fix Suggestion:
Update to version v2.5.0https://github.com/mattermost/mattermost-plugin-agents.git (GITHUB):
Affected version(s) >=v2.2.0 <v2.4.3Fix Suggestion:
Update to version v2.4.3Related Resources (2)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.9
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
PASSIVE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
HIGH
Subsequent System Integrity
HIGH
Subsequent System Availability
HIGH
CVSS v3
Base Score:
8
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
Improper Limitation of a Pathname to a Restricted Directory
EPSS
Base Score:
0.27