The vulnerability is an authentication bypass in MemOS caused by an unset INTERNAL_SERVICE_SECRET environment variable. When AUTH_ENABLED is true but the secret is missing, the is_internal_request() check compares two None values, which evaluates to true. This flaw allows an unauthenticated remote attacker to have the request treated as a trusted internal request and granted full administrative scopes. The attacker can then use the admin API to mint keys, enumerate, revoke, and create a master key, effectively gaining persistent privileged access to all system data.

The affected product is MemTensor’s MemOS, a memory operating system for large language models and AI agents. The issue manifests in deployments where authentication is enabled and the undocumented INTERNAL_SERVICE_SECRET environment variable is left unset. No specific version numbers are provided, so any release before the fix that allows an unset secret is vulnerable.

This flaw has a high severity with a CVSS score of 9.3 and is not listed in the CISA KEV catalog. No EPSS score is available. The likely attack vector is a remote attacker sending unauthenticated HTTP requests to MemOS admin endpoints. By exploiting the open comparison, the attacker can acquire administrative privileges and control over key management and data access. Given the critical privilege escalation and lack of mitigation, the risk is high and exploitation is highly probable in exposed deployments.