The vulnerability exists in vLLM’s /v1/audio/transcriptions endpoint; decompressing a compressed OPUS file produces a massive PCM output that can exceed the server’s memory, causing an out‑of‑memory failure and a denial of service. The flaw is a lack of bounds checking on the decoded output size (CWE‑409). An attacker can trigger the issue by uploading a specially crafted audio file, exhausting memory resources and potentially crashing or rejecting legitimate requests.

vLLM project prior to version 0.23.1rc0, any deployment that exposes the /v1/audio/transcriptions endpoint. The vulnerable product is vllm-project vllm; the flaw affects all environments running the engine before the fixed release.

The CVSS score of 6.5 indicates moderate severity. No EPSS score is available to gauge exploitation likelihood, and the vulnerability is not listed in the CISA KEV catalog. Attackers could exploit this through an HTTP POST to the transcription endpoint, sending a large compressed audio payload to trigger the denial‑of‑service condition.