CVE-2026-9597 | Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4 fail … | CVSS 5.4 MEDIUM

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

Metadata

CVE ID: CVE-2026-9597
State: PUBLISHED
Assigner: Mattermost
Reserved: 2026-05-26 15:15 UTC
Published: 2026-07-13 08:17 UTC
Last updated: 2026-07-13 13:55 UTC
Primary CWE: CWE-305
CWE-305 – Authentication Bypass by Primary Weakness
Vendor / Product: Mattermost / Mattermost
Sources: cve.org · NVD

Severity & Metrics

5.4 MEDIUM CVSS 3.1

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

SSVC — CISA Coordinator

Exploitation: none
Automatable: no
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
Mattermost	Mattermost	—	11.7.0 ≤ 11.7.2, 11.6.0 ≤ 11.6.4, 11.8.0, 11.7.3 …

Weakness (CWE)

CWE	Source	Description
CWE-305	cna	CWE-305 – Authentication Bypass by Primary Weakness

CVSS scores (1)

Score	Severity	Version	Source	Vector
5.4	MEDIUM	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

References (1)

MMSA-2026-00681 https://mattermost.com/security-updates