What is CVE-2026-57173?

CVE-2026-57173 is a medium-severity allocation of resources without limits or throttling vulnerability in vllm (pip), affecting versions <= 0.23.0. It is fixed in 0.24.0. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.

How severe is CVE-2026-57173?

CVE-2026-57173 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which versions of vllm are affected by CVE-2026-57173?

vllm (pip) versions <= 0.23.0 is affected.

Is there a fix for CVE-2026-57173?

Yes. CVE-2026-57173 is fixed in 0.24.0. Upgrade to this version or later.

Is CVE-2026-57173 exploitable, and should I be worried?

Whether CVE-2026-57173 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2026-57173 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

How do I fix CVE-2026-57173?

Upgrade vllm to 0.24.0 or later.

CVE-2026-57173 in vllm

Q: How severe is CVE-2026-57173?

CVE-2026-57173 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Q: Which versions of vllm are affected by CVE-2026-57173?

vllm (pip) versions <= 0.23.0 is affected.

Q: Is there a fix for CVE-2026-57173?

Yes. CVE-2026-57173 is fixed in 0.24.0. Upgrade to this version or later.

Q: Is CVE-2026-57173 exploitable, and should I be worried?

Whether CVE-2026-57173 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2026-57173 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2026-57173?

Upgrade vllm to 0.24.0 or later.

Summary

vLLM: Unauthenticated audio decompression-bomb DoS in /v1/chat/completions

The 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.

Verified against main at HEAD d78650c (2026-06-16); applicable to the latest release v0.23.0.

Details

The guard rejects long audio during decode (before allocation), implemented in vllm/multimodal/media/audio.py:

load_audio_pyav, metadata reject (~82-98) and live sample-count reject (~129-136)
load_audio_soundfile, frames reject (~165-174)

All are gated on if max_duration_s is not None.

It is passed in exactly one place, the transcription serving layer:

# .../speech_to_text/base/serving.py:~170-174
load_audio(buf, sr=..., max_duration_s=self.max_audio_decode_duration_s)
#   self.max_audio_decode_duration_s = envs.VLLM_MAX_AUDIO_DECODE_DURATION_S  (default 600)

The chat path never threads it:

# vllm/multimodal/media/audio.py:237-238
def load_bytes(self, data: bytes) -> tuple[npt.NDArray, float]:
    return load_audio(BytesIO(data), sr=None)   # no max_duration_s -> every guard above is skipped

Unauthenticated reachability chain (chat):
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).

Impact

Unauthenticated 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.

The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.

CVE-2026-57173 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.24.0); upgrading removes the vulnerable code path.

Affected versions

vllm (<= 0.23.0)

Security releases

vllm → 0.24.0 (pip)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

A fix was introduced in this MR: https://github.com/vllm-project/vllm/pull/45908

Frequently Asked Questions

What is CVE-2026-57173? CVE-2026-57173 is a medium-severity allocation of resources without limits or throttling vulnerability in vllm (pip), affecting versions <= 0.23.0. It is fixed in 0.24.0. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
How severe is CVE-2026-57173? CVE-2026-57173 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
Which versions of vllm are affected by CVE-2026-57173? vllm (pip) versions <= 0.23.0 is affected.
Is there a fix for CVE-2026-57173? Yes. CVE-2026-57173 is fixed in 0.24.0. Upgrade to this version or later.
Is CVE-2026-57173 exploitable, and should I be worried? Whether CVE-2026-57173 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2026-57173 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2026-57173? Upgrade vllm to 0.24.0 or later.