CVE-2026-57173: vLLM Denial of Service Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-hcwq-8wjf-3gcr",
  "modified" : "2026-09-16T22:12:18Z",
  "published" : "2026-09-16T22:12:17Z",
  "aliases" : [ "CVE-2026-57173" ],
  "summary" : "vLLM: Unauthenticated audio decompression-bomb DoS in /v1/chat/completions",
  "details" : "### Summary\nThe audio decode-duration guard (`max_duration_s`, env `VLLM_MAX_AUDIO_DECODE_DURATION_S`, default 600s) that protects against audio decompression-bomb DoS is wired into **only** the speech-to-text path (`/v1/audio/transcriptions`). The **chat** audio path (`/v1/chat/completions`, `input_audio` content parts) calls the same decoder with **no** limit, so an **unauthenticated** client can submit a few-KB compressed audio file that expands to multiple GB of float32 PCM at decode time, OOM-killing the worker. This is a distinct sibling of **CVE-2026-5497** (video frame-count bomb, `VideoMediaIO.load_base64`) and **GHSA-pq5c-rjhq-qp7p** (image) in the same media subsystem.\n\nVerified against `main` at HEAD `d78650c` (2026-06-16); applicable to the latest release v0.23.0.\n\n### Details\nThe guard rejects long audio *during* decode (before allocation), implemented in `vllm/multimodal/media/audio.py`:\n- `load_audio_pyav` — metadata reject (~82-98) and live sample-count reject (~129-136)\n- `load_audio_soundfile` — frames reject (~165-174)\n\nAll are gated on `if max_duration_s is not None`.\n\nIt is passed in exactly **one** place — the transcription serving layer:\n```python\n# .../speech_to_text/base/serving.py:~170-174\nload_audio(buf, sr=..., max_duration_s=self.max_audio_decode_duration_s)\n#   self.max_audio_decode_duration_s = envs.VLLM_MAX_AUDIO_DECODE_DURATION_S  (default 600)\n```\n\nThe chat path never threads it:\n```python\n# vllm/multimodal/media/audio.py:237-238\ndef load_bytes(self, data: bytes) -> tuple[npt.NDArray, float]:\n    return load_audio(BytesIO(data), sr=None)   # no max_duration_s -> every guard above is skipped\n```\n\nUnauthenticated reachability chain (chat):\n`parse_input_audio` (`chat_utils.py`) -> `parse_audio` -> `connector.fetch_audio` -> `AudioMediaIO._load_data_url` -> `load_base64` -> `load_bytes` -> `load_audio(..., sr=None)`. The connector never passes `max_duration_s`, and inline `data:` URLs need no HTTP fetch (so `VLLM_AUDIO_FETCH_TIMEOUT` does not bound them). The OpenAI-compatible server has no auth by default (auth only when `--api-key` / `VLLM_API_KEY` is set).\n\n### Impact\nUnauthenticated remote denial of service (availability) via memory amplification on a default-no-auth endpoint, on any deployment serving an audio-capable model. Same class and impact as the sibling CVE-2026-5497 (video). CWE-770 / CWE-409.\n\n### Fix\nA fix was introduced in this MR: https://github.com/vllm-project/vllm/pull/45908",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "vllm"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.24.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.23.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/vllm-project/vllm/security/advisories/GHSA-hcwq-8wjf-3gcr"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-57173"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vllm-project/vllm/pull/45908"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vllm-project/vllm/commit/3d20275bb4d434f53055c3c0b645fd8bb072965e"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/vllm-project/vllm"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vllm-project/vllm/releases/tag/v0.24.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-16T22:12:17Z",
    "nvd_published_at" : "2026-09-16T17:17:24Z"
  }
}