CVE-2026-3590
Published:April 15, 2026
Updated:April 23, 2026
Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link tokens, which allows an attacker with access to a valid magic link to establish multiple independent authenticated sessions via concurrent requests.. Mattermost Advisory ID: MMSA-2026-00624
Affected Packages
github.com/mattermost/mattermost (GO):
Affected version(s) >=v10.11.0 <v10.11.13Fix Suggestion:
Update to version v10.11.13github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.3.0 <v11.3.3Fix Suggestion:
Update to version v11.3.3github.com/mattermost/mattermost (GO):
Affected version(s) >=v11.4.0 <v11.4.3Fix Suggestion:
Update to version v11.4.3github.com/mattermost/mattermost (GO):
Affected version(s) =v11.5.0 <v11.5.1Fix Suggestion:
Update to version v11.5.1Related 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
NONE
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
6.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Time-of-check Time-of-use (TOCTOU) Race Condition
EPSS
Base Score:
0.03
