CVE-2026-3224 in Server
Summary
by MITRE • 03/04/2026
Authentication bypass in the Microsoft Entra ID (Azure AD) authentication mode in Devolutions Server 2025.3.15.0 and earlier allows an unauthenticated user to authenticate as an arbitrary Entra ID user via a forged JSON Web Token (JWT).
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Analysis
by VulDB Data Team • 03/11/2026
The vulnerability identified as CVE-2026-3224 represents a critical authentication bypass flaw within Devolutions Server version 2025.3.15.0 and earlier releases. This issue specifically affects the Microsoft Entra ID (formerly Azure AD) authentication integration, creating a pathway for unauthorized access that fundamentally undermines the security posture of systems relying on this authentication mechanism. The flaw enables an attacker to forge JSON Web Tokens that are accepted by the system, effectively allowing them to impersonate any valid Entra ID user account without proper credentials or authorization. This vulnerability directly impacts the integrity of the authentication process and represents a severe deviation from expected security controls.
The technical root cause of this vulnerability lies in the improper validation of JSON Web Tokens within the Devolutions Server's Entra ID authentication implementation. When the system processes authentication requests, it fails to adequately verify the authenticity and integrity of the JWTs presented by clients. This weakness allows attackers to craft malicious tokens that contain forged claims and signatures, which the server accepts as legitimate authentication credentials. The vulnerability stems from inadequate cryptographic validation mechanisms and insufficient token verification procedures that should normally ensure the token originates from a trusted identity provider. According to CWE classification, this represents a weakness in authentication mechanisms, specifically categorized under CWE-287 for improper authentication and CWE-347 for flawed cryptographic signature verification. The flaw essentially creates a trust boundary violation where the system cannot distinguish between legitimate and forged authentication tokens.
The operational impact of this vulnerability is substantial and far-reaching across organizations utilizing Devolutions Server with Entra ID integration. An attacker exploiting this vulnerability can gain unauthorized access to sensitive systems, data, and resources that are protected by Entra ID authentication controls. This authentication bypass enables lateral movement within networks, privilege escalation opportunities, and potential data exfiltration from systems that should only be accessible to authorized users. The attack vector is particularly dangerous because it requires no prior authentication credentials, making it accessible to any attacker with network access to the vulnerable system. The vulnerability also aligns with ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting, as it allows adversaries to obtain system access through forged authentication tokens rather than traditional credential compromise methods. Organizations may experience unauthorized access to critical infrastructure, potentially leading to regulatory compliance violations, data breaches, and significant financial and reputational damage.
Mitigation strategies for this vulnerability require immediate action from affected organizations to implement security patches and configuration updates from Devolutions. The primary solution involves upgrading to a patched version of Devolutions Server that properly validates JWT signatures and implements robust token verification mechanisms. Network segmentation and monitoring should be enhanced to detect unusual authentication patterns that might indicate exploitation attempts. Organizations should also implement additional authentication layers such as multi-factor authentication to reduce the impact of potential token forgery. Security teams must conduct thorough vulnerability assessments to identify systems that may be exposed to this attack vector and establish monitoring procedures for anomalous authentication activity. The implementation of proper JWT validation including signature verification, audience checking, and issuer validation should be enforced across all authentication integrations. Additionally, organizations should review their access controls and privilege assignments to ensure that even if an attacker successfully exploits this vulnerability, their access scope remains limited and monitored. Regular security testing and penetration testing should be conducted to verify that the implemented mitigations are effective against similar authentication bypass vulnerabilities.