CVE-2026-54233

Name of the Vulnerable Software and Affected Versions vLLM versions prior to 0.23.1rc0

Description The '/v1/audio/transcriptions' endpoint limits the size of compressed uploads but fails to limit the size of the decoded PCM (Pulse Code Modulation) output. PCM is an uncompressed digital audio format. The SpeechToTextProcessor rejects uploads exceeding the VLLM MAX AUDIO CLIP FILESIZE MB limit based on compressed byte length; however, the audio decoder in audio.py accumulates all decoded frames into memory without a size limit. For example, a 25MB OPUS file can expand to approximately 14.9GB of float32 PCM during decode time because the np.concatenate function allocates a second contiguous array. The SpeechToTextConfig.max audio clip s limit is only applied after the full decode process, which does not prevent the initial memory allocation. This allows an unauthenticated attacker to exhaust server memory using a small number of concurrent requests that stay within the documented upload size limits.

Recommendations Update to version 0.23.1rc0 or later.