The vulnerability in sglang (up to version 0.5.19) arises from a failure to validate bootstrap_room values in the prefill/decode disaggregation mode when using the Mooncake KV transfer backend. Attackers without authentication can access the decode engine's POST /generate endpoint and supply arbitrary bootstrap_room values. This leads to unbounded allocation of transfer state memory, which can exhaust the prefill process memory and cause the process to terminate due to out-of-memory conditions. The CVSS 4.0 base score is 8.7, indicating a high severity with network attack vector, no privileges or user interaction required, and high impact on availability.

Successful exploitation results in denial of service by exhausting memory resources of the prefill process, causing out-of-memory termination. This disrupts normal operation of the sglang decode engine, impacting availability. There is no indication of confidentiality or integrity impact. The vulnerability can be triggered remotely without authentication.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict access to the decode engine's POST /generate endpoint to trusted users or networks to prevent unauthenticated exploitation. Monitor resource usage to detect potential exploitation attempts.