---
title: "CVE-2026-94623: vLLM - Denial of Service"
description: "vLLM through 0.29.0 contains a denial of service vulnerability caused by improper validation of block counts in the NIXL connector's prefix caching during multi-prompt completion requests, letting attackers cause worker termination, exploit requires crafted multi-prompt requests."
url: https://panop.io/threat-heartbeat/CVE-2026-94623/
---

# CVE-2026-94623 vLLM - Denial of Service

vLLM through 0.29.0 contains a denial of service vulnerability caused by improper validation of block counts in the NIXL connector's prefix caching during multi-prompt completion requests, letting attackers cause worker termination, exploit requires crafted multi-prompt requests.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.63% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-94623)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Published

21 September 2026

Updated

15 October 2026

Weakness

[CWE-617](https://cwe.mitre.org/data/definitions/617.html)

## Vendor fix

Update to the latest version beyond 0.29.0.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-94623](https://nvd.nist.gov/vuln/detail/CVE-2026-94623)
- [https://github.com/vllm-project/vllm](https://github.com/vllm-project/vllm)
- [https://github.com/vllm-project/vllm/blob/v0.29.0/vllm/distributed/kv\_transfer/kv\_connector/v1/nixl/base\_worker.py#L2642-L2646](https://github.com/vllm-project/vllm/blob/v0.29.0/vllm/distributed/kv_transfer/kv_connector/v1/nixl/base_worker.py#L2642-L2646)
- [https://github.com/vllm-project/vllm/pull/51505](https://github.com/vllm-project/vllm/pull/51505)
- [https://www.vulncheck.com/advisories/vllm-through-0.29.0-denial-of-service-via-nixl-multi-prompt-assertion-failure](https://www.vulncheck.com/advisories/vllm-through-0.29.0-denial-of-service-via-nixl-multi-prompt-assertion-failure)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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