CVE-2026-3590CWE-367

Race Condition in Guest Magic Link Authentication Allows Token Reuse

Medium · published April 15, 2026

CVSS v3.1
6.5
EPSS
0%
Percentile
13.0
In the wild
Unconfirmed
What it is

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

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00230 · 13.0th percentile
Weakness
CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition
Published
2026-04-15T11:00Z
EPSS history
Timeline
  • 15 APR 11:00Z
    Race Condition in Guest Magic Link Authentication Allows Token Reuse
    cvelistv5