Improper Authentication in lunary-ai/lunary

The impact of CVE-2025-9803 is severe, enabling attackers to completely take over user accounts within the lunary application. An attacker could exploit this vulnerability by crafting a malicious application that requests Google OAuth authentication. Upon successful authentication, the attacker's application would receive an access token. Due to the missing 'aud' validation, this token can be used to impersonate the legitimate user, granting the attacker full access to their data and functionality within lunary. This could include accessing sensitive information, modifying user settings, or performing actions on behalf of the compromised user. The blast radius extends to all users of affected lunary versions who utilize Google OAuth for authentication.

Organizations and individuals using lunary for AI-powered tasks and relying on Google OAuth for authentication are at risk. This includes users who have not yet upgraded to the latest version (1.9.35) and those who have not implemented additional security measures to mitigate the risk of account takeover.

• python / server: Examine lunary application logs for OAuth authentication attempts with invalid 'aud' values. Use Python's requests library to test the OAuth endpoint and verify 'aud' validation.

import requests

# Replace with your lunary instance URL
url = 'https://your-lunary-instance/oauth/token'

# Replace with your client ID and secret
client_id = 'your_client_id'
client_secret = 'your_client_secret'

# Malformed token
token = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJleGFtcGxlIiwibmJmIjoxNjk4NzQ4ODAwLCJleHAiOjE2OTg3NzA4MDAsImlnaGxpZmViVXNlcm5hbWUiOiJodHRwczovL3dvc3RhbmQuZ2UiLCJzY29wZSI6WyJtYWljYWwtdG9rZW4uY29jkzsifQ.xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'

headers = {'Content-Type': 'application/x-www-form-urlencoded'}
data = {'grant_type': 'urn:ietf:params:oauth:grant-type:jwt-bearer', 'assertion': token, 'client_id': client_id, 'client_secret': client_secret}

response = requests.post(url, headers=headers, data=data)

print(response.status_code)
print(response.text)

• generic web: Monitor access logs for requests to the OAuth token endpoint with unusual parameters or user agents. Check for unusual patterns in OAuth authentication attempts.

1. 2025-11-25Disclosure

   disclosure

1. Reserviert2025-09-01
2. Veröffentlicht2025-11-25
3. EPSS aktualisiert2026-03-23

The primary mitigation for CVE-2025-9803 is to immediately upgrade lunary to version 1.9.35 or later. If upgrading is not immediately feasible, consider implementing temporary workarounds such as restricting access to sensitive functionalities or implementing stricter authentication policies. While a WAF cannot directly address this code-level vulnerability, it could be configured to monitor for suspicious OAuth token activity. Thoroughly review and audit the Google OAuth integration code to ensure proper 'aud' validation is implemented in future development cycles. After upgrading, confirm the fix by attempting to authenticate with a known valid Google OAuth application and verifying that the 'aud' field is correctly validated.