CVE-2024-5270 in Mattermost
Summary
by MITRE • 05/26/2024
Mattermost versions 9.5.x <= 9.5.3, 9.7.x <= 9.7.1, 9.6.x <= 9.6.1 and 8.1.x <= 8.1.12 fail to check if the email signup configuration option is enabled when a user requests to switch from SAML to Email. This allows the user to switch their authentication mail from SAML to email and possibly edit personal details that were otherwise non-editable and provided by the SAML provider.
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Analysis
by VulDB Data Team • 09/30/2025
This vulnerability exists in Mattermost server versions across multiple release branches including 8.1.x up to 8.1.12, 9.5.x up to 9.5.3, 9.6.x up to 9.6.1, and 9.7.x up to 9.7.1. The flaw represents a critical authorization bypass that occurs when users attempt to transition their authentication method from SAML (Security Assertion Markup Language) to email-based authentication. The core technical issue stems from the absence of proper validation checks within the authentication switching mechanism, specifically failing to verify whether the email signup configuration option has been enabled in the system settings. This oversight creates a pathway for unauthorized modification of user attributes that were originally provisioned through SAML identity providers.
The operational impact of this vulnerability extends beyond simple authentication method switching as it enables attackers to manipulate user personal information that would normally remain immutable when sourced from external identity providers. When users transition from SAML to email authentication, they can potentially edit fields that were originally populated by the SAML provider such as display names, email addresses, and other profile information that should remain controlled by the identity management system. This creates a significant security risk as it allows for potential credential hijacking, profile manipulation, and unauthorized access to system resources that may have been restricted based on SAML-provided attributes. The vulnerability directly violates the principle of least privilege and undermines the integrity of user identity management within the Mattermost environment.
From a cybersecurity framework perspective, this vulnerability maps to CWE-639 (Authorization Bypass Through User Attributes) and aligns with ATT&CK technique T1078.004 (Valid Accounts: Cloud Accounts) where attackers can leverage legitimate user accounts to gain unauthorized access to system resources. The flaw represents a configuration management issue that allows for privilege escalation through user attribute manipulation, potentially enabling attackers to modify user roles, permissions, and access levels that were originally controlled by external identity providers. Organizations using Mattermost in environments with strict identity governance policies face particular risk as this vulnerability can be exploited to bypass security controls that depend on external identity provider attributes.
Mitigation strategies should focus on immediate implementation of security patches provided by Mattermost for affected versions, alongside configuration reviews to ensure proper email signup settings are enforced. System administrators should implement strict access controls and monitoring of authentication method switching activities, particularly for users who have previously authenticated via SAML. Additional protective measures include implementing automated alerts for authentication method changes, conducting regular security audits of user attribute modifications, and ensuring that identity provider configurations properly restrict user attribute editing capabilities. Organizations should also consider implementing multi-factor authentication controls and maintaining detailed audit logs to detect and respond to unauthorized attribute modifications that may indicate exploitation of this vulnerability.