Mattermost versions 10.10.x <= 10.10.1, 10.5.x <= 10.5.9, 10.9.x <= 10.9.4 fail to validate the redirect_to parameter, allowing an attacker to craft a malicious link that, once a user authenticates with their SAML provider, could post the user’s cookies to an attacker-controlled URL.
Advisories
Source ID Title
EUVD EUVD EUVD-2025-29171 Mattermost Open Redirect vulnerability
Github GHSA Github GHSA GHSA-69j8-prx2-vx98 Mattermost Open Redirect vulnerability
Fixes

Solution

Update Mattermost to versions 10.11.0, 10.10.2, 10.5.10, 10.9.5 or higher.


Workaround

No workaround given by the vendor.

References
History

Wed, 17 Sep 2025 11:00:00 +0000

Type Values Removed Values Added
First Time appeared Mattermost mattermost
Vendors & Products Mattermost mattermost

Tue, 16 Sep 2025 16:15:00 +0000

Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost Server
CPEs cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Vendors & Products Mattermost
Mattermost mattermost Server

Mon, 15 Sep 2025 12:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Mon, 15 Sep 2025 10:45:00 +0000

Type Values Removed Values Added
Description Mattermost versions 10.10.x <= 10.10.1, 10.5.x <= 10.5.9, 10.9.x <= 10.9.4 fail to validate the redirect_to parameter, allowing an attacker to craft a malicious link that, once a user authenticates with their SAML provider, could post the user’s cookies to an attacker-controlled URL.
Title One-Click Mattermost Account Takeover via Poisoned RelayState SAML Parameter
Weaknesses CWE-601
References
Metrics cvssV3_1

{'score': 7.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:L'}


cve-icon MITRE

Status: PUBLISHED

Assigner: Mattermost

Published:

Updated: 2025-09-15T12:06:57.518Z

Reserved: 2025-08-15T14:59:12.540Z

Link: CVE-2025-9072

cve-icon Vulnrichment

Updated: 2025-09-15T12:04:08.711Z

cve-icon NVD

Status : Analyzed

Published: 2025-09-15T11:15:34.183

Modified: 2025-09-16T16:00:26.390

Link: CVE-2025-9072

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2025-09-17T10:08:39Z