CVE-2026-3590

MEDIUM

Race Condition in Guest Magic Link Authentication Allows Token Reuse

Title source: cna

Description

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

References (1)

[Vendor Advisory] https://mattermost.com/security-updates

Scores

CVSS v3 6.5

EPSS 0.0003

EPSS Percentile 10.0%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CISA SSVC

Vulnrichment

Exploitation none

Automatable yes

Technical Impact partial

Details

CWE

CWE-367

Status published

Products (10)

Mattermost/Mattermost 10.11.0 - 10.11.12

Mattermost/Mattermost 10.11.13

Mattermost/Mattermost 11.3.0 - 11.3.2

Mattermost/Mattermost 11.3.3

Mattermost/Mattermost 11.4.0 - 11.4.2

Mattermost/Mattermost 11.4.3

Mattermost/Mattermost 11.5.0

Mattermost/Mattermost 11.5.1

Mattermost/Mattermost 11.6.0

mattermost/mattermost_server 10.11.0 - 10.11.13

Published Apr 15, 2026

Tracked Since Apr 15, 2026