CVE-2025-9072

One-Click Mattermost Account Takeover via Poisoned RelayState SAML Parameter

Published Sep 15, 2025 CVSS 3.1 · 7.6 High EPSS < 1% KEV · Not listed
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.

Remediation

Vendor Solution

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

Tracking

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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
References
History
Type Values Removed Values Added
First Time appeared Mattermost mattermost
Vendors & Products Mattermost mattermost
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
Type Values Removed Values Added
Metrics ssvc

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

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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Mattermost
Published
Updated
Sep 15, 2025, 12:06 PM
Reserved
Aug 15, 2025, 2:59 PM
Status
Analyzed
Published
Sep 15, 2025, 11:15 AM
Modified
Oct 19, 2026, 5:10 PM