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CVE-2026-9597

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

Published: Jul 13, 2026Updated: Jul 13, 2026 Sources: CVE List NVDCWE-305
5.4MEDIUM
NVD MITRE
EPSS Score
0.1%
Top 96.1%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

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

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:LI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-305

Affected Products

Mattermost
commercial·US
MattermostOn-premWeb App
Communications / messaging-chat
mattermost serverOn-premWeb App
Communications / messaging-chat

Exploitability

Official Patch Available
Is your org exposed to CVE-2026-9597?We can run the check for you — a free external exposure review, no install. Check my exposure

References

https://mattermost.com/security-updates
mattermost.com

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