CVE-2016-6582 in Doorkeeper Gem
Summary
by MITRE
The Doorkeeper gem before 4.2.0 for Ruby might allow remote attackers to conduct replay attacks or revoke arbitrary tokens by leveraging failure to implement the OAuth 2.0 Token Revocation specification.
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Analysis
by VulDB Data Team • 05/14/2026
The Doorkeeper gem represents a critical authentication framework for ruby applications implementing oauth 2.0 protocols. This vulnerability affects versions prior to 4.2.0 and exposes applications to significant security risks through improper implementation of the oauth 2.0 token revocation specification. The flaw stems from the gem's failure to correctly handle token revocation requests, creating opportunities for malicious actors to exploit the authentication flow. When applications rely on doorkeeper for oauth 2.0 token management, they become vulnerable to attacks that can compromise session integrity and user authentication states. The vulnerability specifically targets the token revocation mechanism, which should follow established oauth 2.0 standards to ensure proper token lifecycle management.
The technical implementation flaw manifests in the gem's inability to properly validate and process token revocation requests according to the oauth 2.0 specification. This creates a scenario where attackers can manipulate the token lifecycle by either replaying previously valid tokens or revoking tokens that they do not possess legitimate rights to revoke. The vulnerability essentially allows unauthorized parties to manipulate the token state within the authorization server, undermining the fundamental security guarantees that oauth 2.0 protocols are designed to provide. This misimplementation creates a path for attackers to maintain access to systems beyond the normal token expiration times or to prematurely invalidate legitimate user sessions.
From an operational impact perspective, this vulnerability can lead to persistent unauthorized access to protected resources and services. Attackers who exploit this flaw can conduct replay attacks that allow them to reuse valid tokens indefinitely, effectively bypassing session timeout mechanisms and authorization controls. Additionally, the token revocation capability can be abused to invalidate legitimate user tokens, potentially causing denial of service conditions or unauthorized access to privileged systems. The vulnerability affects applications that depend on doorkeeper for secure authentication, potentially compromising user data, system integrity, and business operations. Organizations using vulnerable versions may experience unauthorized access to sensitive information and services, as the authentication mechanism fails to properly enforce token lifecycle management.
Security mitigations for this vulnerability primarily involve upgrading to doorkeeper version 4.2.0 or later, which contains the proper implementation of the oauth 2.0 token revocation specification. Organizations should conduct immediate vulnerability assessments to identify applications using affected versions and implement the necessary updates as part of their patch management processes. Additional defensive measures include monitoring authentication logs for unusual token revocation patterns, implementing proper access controls for token management endpoints, and ensuring that all oauth 2.0 implementations follow established security best practices. The vulnerability aligns with CWE-305 authentication weakness patterns and represents a significant risk under ATT&CK framework's privilege escalation and credential access techniques. Organizations should also consider implementing additional security controls such as token binding, secure token storage mechanisms, and comprehensive monitoring of authentication events to detect and respond to potential exploitation attempts.