CVE-2026-9597

MEDIUM

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

Title source: cna
STIX 2.1

Description

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

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory
MMSA-2026-00681
https://mattermost.com/security-updates

Scores

CVSS v3 5.4
EPSS 0.0014
EPSS Percentile 3.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-305
Status published
Products (6)
Mattermost/Mattermost 11.6.0 - 11.6.4
Mattermost/Mattermost 11.6.5
Mattermost/Mattermost 11.7.0 - 11.7.2
Mattermost/Mattermost 11.7.3
Mattermost/Mattermost 11.8.0
mattermost/mattermost_server 11.6.0 - 11.6.5
Published Jul 13, 2026
Tracked Since Jul 13, 2026