CVE-2026-27656

Published: Mar 25, 2026 Last Modified: Mar 25, 2026
ExploitDB:
Other exploit source:
Google Dorks:
MEDIUM 5,7
Source: [email protected]
Attack Vector: network
Attack Complexity: high
Privileges Required: high
User Interaction: required
Scope: unchanged
Confidentiality: high
Integrity: high
Availability: none

Description

AI Translation Available

Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to properly validate user identity in the OpenID {{IsSameUser()}} comparison logic, which allows an attacker to take over arbitrary user accounts via an overly permissive substring matching flaw in the user discovery flow.. Mattermost Advisory ID: MMSA-2026-00590

303

Incorrect Implementation of Authentication Algorithm

Draft
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Access Control
Potential Impacts:
Bypass Protection Mechanism
Applicable Platforms
All platforms may be affected
View CWE Details
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