CVE-2025-9803 in lunary
Summary
by MITRE • 11/25/2025
lunary-ai/lunary version 1.9.34 is vulnerable to an account takeover due to improper authentication in the Google OAuth integration. The application fails to verify the 'aud' (audience) field in the access token issued by Google, which is crucial for ensuring the token is intended for the application. This oversight allows attackers to use tokens issued to malicious applications to gain unauthorized access to user accounts. The issue is resolved in version 1.9.35.
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Analysis
by VulDB Data Team • 12/30/2025
The vulnerability identified as CVE-2025-9803 affects the lunary-ai/lunary application version 1.9.34 and represents a critical authentication flaw within the Google OAuth integration mechanism. This issue stems from the application's failure to properly validate the audience field within OAuth access tokens, creating a significant security gap that directly enables account takeover attacks. The flaw demonstrates a fundamental misunderstanding of OAuth security principles where the application accepts tokens without verifying that they were issued specifically for the intended application, thereby undermining the core security model of the OAuth protocol.
The technical implementation of this vulnerability occurs when the application processes Google OAuth access tokens without performing the necessary audience validation check. In standard OAuth 2.0 implementations, the aud field within the token payload serves as a critical security mechanism that ensures tokens are intended for specific recipients rather than being universally applicable. When the application fails to verify this field, attackers can potentially substitute tokens issued to other applications or services, exploiting the trust relationship between Google and the application. This misconfiguration creates an environment where any valid token from Google's OAuth service can be leveraged to access user accounts, effectively bypassing the intended authentication flow.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential data breaches and user account compromise. Attackers exploiting this flaw can gain full access to user accounts and associated data without proper authorization, potentially leading to privacy violations, data exfiltration, and service abuse. The vulnerability is particularly concerning because it affects the core authentication mechanism of the application, meaning that any user who authenticates through Google OAuth could be at risk. This type of flaw aligns with CWE-345 Insufficient Verification of Data Authenticity, which specifically addresses the failure to properly verify the authenticity and integrity of data inputs, including security tokens.
The security implications of this vulnerability can be analyzed through the lens of the MITRE ATT&CK framework, where this issue maps to techniques involving credential access and privilege escalation. Attackers could potentially use this vulnerability to establish persistent access to user accounts, leveraging the compromised authentication mechanism to maintain long-term access to sensitive resources. The fix implemented in version 1.9.35 addresses this by enforcing proper validation of the audience field, ensuring that access tokens are only accepted when they explicitly indicate that the token is intended for the specific application instance. This remediation aligns with best practices for OAuth security implementation and follows the principle of least privilege by ensuring that tokens can only be used within their intended scope.
Organizations using affected versions of the lunary application should prioritize immediate remediation to protect user accounts from potential exploitation. The vulnerability represents a clear failure in the security architecture and demonstrates the importance of implementing proper token validation mechanisms. Security teams should conduct comprehensive reviews of their OAuth implementations to ensure similar flaws are not present in other authentication flows. The fix serves as a reminder of the critical importance of adhering to established security standards and protocols, particularly when dealing with third-party authentication services that provide tokens with specific security attributes designed to prevent exactly this type of exploitation.