CVE-2026-85392 in Peppermint
Summary
by MITRE • 09/03/2026
Peppermint through 0.5.5 contains an authorization bypass vulnerability in the GET /api/v1/auth/user/:id/logout endpoint that allows authenticated attackers to delete sessions for any user by supplying arbitrary user IDs. Attackers can forcibly log out any user including administrators by calling the logout handler with another user's ID, since the endpoint performs no authorization checks to verify the caller owns the target account.
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Analysis
by VulDB Data Team • 09/03/2026
The vulnerability identified in Peppermint versions through 0.5.5 represents a critical failure in server-side access control mechanisms, specifically manifesting as an insecure direct object reference within the authentication subsystem. The core technical flaw resides in the GET /api/v1/auth/user/:id/logout endpoint, which is designed to terminate active user sessions. However, the implementation fails to validate whether the authenticated principal making the request possesses administrative privileges or ownership over the target resource identified by the :id parameter. This absence of authorization checks allows any validly authenticated attacker to manipulate the session management logic by supplying arbitrary user identifiers in the URL path. Consequently, the server processes these requests without verifying that the caller is authorized to act on behalf of the specified user account, leading to a complete bypass of intended security boundaries.
From an operational perspective, this vulnerability enables attackers to perform denial-of-service attacks against specific users or administrative accounts by forcibly invalidating their active sessions. By repeatedly calling the logout endpoint with different user IDs, an attacker can disrupt legitimate business operations and degrade system availability for targeted individuals. More critically, if administrators are logged in at the time of exploitation, forcing them out may interrupt critical workflows or potentially create a window of opportunity for further attacks during re-authentication processes. While this specific vector does not directly grant unauthorized access to data, it undermines the integrity of the authentication state and can be leveraged as part of a broader attack chain to escalate privileges or disrupt service continuity.
This flaw aligns with CWE-284, which describes Improper Access Control, specifically highlighting scenarios where an actor is able to bypass intended restrictions on accessing resources. In terms of offensive security frameworks, this behavior corresponds to the ATT&CK technique T1078, Valid Accounts, as it relies on existing valid credentials but abuses them against unauthorized targets. It also reflects aspects of T1534, Internal Spearphishing, if used in conjunction with social engineering to trick an administrator into clicking a malicious link that triggers this endpoint, although the primary classification remains within improper access control due to the lack of server-side validation.
To mitigate this vulnerability, developers must implement strict authorization checks on all endpoints that modify or interact with user-specific resources. The logout handler should verify that the authenticated session's user ID matches the target user ID provided in the request parameters before proceeding with session termination. Additionally, implementing role-based access control can restrict such actions to administrative users only if cross-user session management is a required feature. Input validation alone is insufficient; server-side authorization logic must explicitly confirm ownership or permission rights for every operation involving external identifiers. Regular security audits and static code analysis focused on object reference handling are recommended to prevent similar flaws in future development cycles.