CVE-2026-103765 describes a missing authentication vulnerability in the kvcache-ai Mooncake product through version 0.3.13.post1. The vulnerability exists in the HTTP metadata server's /metadata handler, which does not enforce authentication, enabling unauthenticated attackers to manipulate transfer engine metadata keys. Attackers can poison segment descriptors such as tcp_data_port or re-create rpc_meta entries, which may redirect KV cache transfers to attacker-controlled endpoints or cause server memory exhaustion.

The vulnerability allows unauthenticated attackers to read, modify, and delete critical metadata keys used by the transfer engine. This can lead to redirection of KV cache transfers to malicious listeners, potentially compromising data integrity or confidentiality. Additionally, attackers may exhaust server memory resources, impacting availability.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict access to the HTTP metadata server /metadata handler to trusted users or networks to prevent unauthenticated access.