CVE-2026-79673 in Ech0
Summary
by MITRE • 08/25/2026
Ech0 before 4.4.3 protects the PUT /user endpoint with the profile:read scope, a read-only scope, but allows write operations including password changes. An attacker with an admin's profile:read access token can change the admin's password and login to obtain an unrestricted session token that bypasses all scope enforcement.
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Analysis
by VulDB Data Team • 08/25/2026
The vulnerability identified in Ech0 versions prior to 4.4.3 represents a critical failure in API authorization logic, specifically within the user management endpoint architecture. The core issue stems from a misconfiguration where the PUT /user endpoint is protected by the profile:read scope during access control checks. In standard OAuth2 and OpenID Connect implementations, scopes are intended to define granular permissions for accessing resources or performing actions. A read-only scope like profile:read should strictly limit interactions to retrieving data without modifying it. However, in this specific implementation, the server fails to enforce method-based restrictions relative to the granted scope. This architectural flaw allows any client possessing a valid access token with only the profile:read permission to execute HTTP PUT requests against the user endpoint.
From a technical perspective, this is an instance of Broken Object Level Authorization combined with insufficient control over API methods. The server validates that the incoming request carries a token associated with the correct scope but neglects to verify whether the action implied by the HTTP method aligns with the permissions granted by that scope. Consequently, write operations such as updating user attributes or changing passwords are processed successfully despite the attacker only having read privileges. This bypasses the intended security boundary established by the identity provider and the application's own authorization policies. The flaw effectively treats all authenticated requests within a specific endpoint path as equally permissible regardless of their operational intent, provided they carry the requisite scope for mere existence on that path.
The operational impact of this vulnerability is severe due to its potential for privilege escalation. An attacker who has compromised or obtained an admin's profile:read access token can exploit this flaw to change the administrator's password. By resetting the credentials, the attacker gains full control over the administrative account. This leads directly to a complete compromise of system integrity and confidentiality. Once authenticated as an unrestricted user, the attacker obtains session tokens that bypass all scope enforcement mechanisms entirely. This means subsequent actions are not limited by any predefined permissions, allowing for arbitrary data manipulation, exfiltration of sensitive information, or deployment of malicious configurations across the platform.
This vulnerability aligns with CWE-269 Improper Privilege Management and CWE-862 Missing Authorization in the Common Weakness Enumeration database. It also maps to MITRE ATT&CK technique T1078 Valid Accounts, specifically within the context of account manipulation or persistence through credential theft via API abuse. The attack vector is remote and requires no special environmental conditions other than network access to the vulnerable endpoint and possession of a valid read-only token for an administrative user.
Mitigation strategies must focus on strict enforcement of HTTP method-to-scope mappings. Developers should implement middleware that explicitly checks if the requested action corresponds to the permissions granted by the scope. For endpoints handling sensitive data or state changes, it is imperative to require write-specific scopes such as profile:write or admin privileges for PUT and POST requests. Additionally, implementing role-based access control at the controller level rather than relying solely on token-scoped annotations can provide a more robust defense layer. Regular security audits of API definitions and automated testing that validates both read and write operations against their respective scope requirements are essential to prevent similar misconfigurations in future releases.