CVE-2026-9597CWE-305

Deactivated guest accounts can authenticate via magic-link token in Mattermost REST API login endpoint

Medium · published July 13, 2026

CVSS v3.1
5.4
EPSS
0%
Percentile
13.1
In the wild
Unconfirmed
What it is

Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4 fail to verify whether a guest account is deactivated before creating a session in the magic-link token login path, which allows a deactivated guest user to obtain a fully functional session via a magic-link token issued prior to deactivation.. Mattermost Advisory ID: MMSA-2026-00681

The record
Technical detail
CVSS v3.1
5.4 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00230 · 13.1th percentile
Weakness
CWE-305 · Authentication Bypass by Primary Weakness
Published
2026-07-13T08:17Z
EPSS history
Timeline
  • 13 JUL 08:17Z
    Deactivated guest accounts can authenticate via magic-link token in Mattermost REST API login endpoint
    cvelistv5