If the INTERNAL_SERVICE_SECRET variable is not explicitly configured by the administrator, the os.getenv call returns None. Simultaneously, a request lacking the X-Internal-Service header also results in None. Consequently, the comparison None == None evaluates to true, causing the middleware to improperly classify an unauthenticated external request as a trusted internal principal with "all" scopes. This flaw grants attackers full access to sensitive administrative endpoints, including those for API-key management, allowing them to mint, enumerate, and revoke keys, or generate a master key for persistent, privileged unauthorized access to the entire data platform.

Attack Chain

1. Attacker performs reconnaissance to identify a MemOS deployment exposing the API surface.
2. Attacker probes the authentication middleware by sending arbitrary requests without the X-Internal-Service header.
3. The server-side auth.py middleware retrieves the value of the unset INTERNAL_SERVICE_SECRET environment variable, which resolves to None.
4. The middleware retrieves the missing header value from the request, which also resolves to None.
5. The is_internal_request() function executes the comparison None == None, returning True.
6. The MemOS middleware grants the request a trusted internal principal identity with broad "all" scopes.
7. Attacker submits requests to the /api/key-management endpoint to mint new administrative API keys.
8. Attacker uses the newly minted keys to exfiltrate data or gain persistent, unauthorized administrative access.

Impact

Successful exploitation of this vulnerability leads to complete compromise of the MemOS instance. An attacker can bypass all authentication controls, gain administrative access to API-key management, and exfiltrate or manipulate LLM/agent memory data. Given the "all" scope granted, attackers can generate persistent master keys, effectively providing long-term unauthorized access even if the underlying environment configuration is eventually corrected.

Recommendation

Prioritize the immediate remediation of affected MemOS instances.

• Deploy an INTERNAL_SERVICE_SECRET environment variable with a strong, high-entropy secret key immediately to force the os.getenv return value to be non-null.
• Review all logs for unauthorized access to administrative paths (e.g., /api/key-management) originating from external IP addresses.
• Audit all active API keys in the MemOS deployment for unauthorized additions or modifications created since the deployment was initialized.
• Upgrade MemOS to the patched version once released by the vendor to enforce robust header validation.