LiteLLM versions up to and including 1.86.0 ship with a default master API key 'sk-1234' embedded in the example environment configuration and docker-compose files. This key bypasses all authentication, granting full administrative privileges on the AI Gateway. The authentication code compares the provided API key to this master key without any startup validation or forced rotation, allowing attackers with knowledge of the default key to generate admin API keys, access all stored credentials for integrated LLM providers, perform inference calls billed to the victim, and modify or delete models. The vulnerability is publicly disclosed on Reddit and GitHub, with no official patch or mitigation from the vendor at this time.

An attacker with knowledge of the default master API key can fully compromise the LiteLLM AI Gateway, gaining unrestricted administrative access. This includes generating unlimited API keys, accessing sensitive provider credentials, making unauthorized inference calls billed to the victim, viewing detailed spend logs, and altering or deleting AI models. The exposure of hundreds of publicly accessible instances with default configurations significantly increases the risk of widespread exploitation. No known exploits in the wild have been reported yet.

As of the latest information, there is no official patch or fix available from the vendor. Users deploying LiteLLM must immediately change the default master API key from 'sk-1234' to a strong, unique value before exposing the service. It is critical to avoid deploying LiteLLM with the default .env.example configuration or docker-compose setup without modification. Monitor the vendor's GitHub issue tracker for updates and official remediation guidance. Patch status is not yet confirmed — check the vendor advisory or repository for current remediation guidance.