CVE-2026-94623

HIGH 7.5

vLLM through 0.29.0 Denial of Service via NIXL Multi-Prompt Assertion Failure

CVSS Score

7.5

EPSS Score

0.0%

EPSS Percentile

0th

vLLM through 0.29.0 contains a denial of service vulnerability in the NIXL connector's prefix caching implementation that fails to properly validate block counts across multi-prompt completion requests in prefill/decode disaggregated deployments. Attackers can trigger an assertion failure in NixlBaseConnectorWorker._apply_prefix_caching by submitting completion requests with multiple prompts of varying lengths, causing the decode worker to terminate and become unavailable until restarted.

CWE	CWE-617
Vendor	vllm-project
Product	vllm
Published	Sep 21, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

vllm-project / vllm

0 ≤ 0.29.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/vllm-project/vllm/pull/51505 github.com: https://github.com/vllm-project/vllm/blob/v0.29.0/vllm/distributed/kv_transfer/kv_connector/v1/nixl/base_worker.py#L2642-L2646 github.com: https://github.com/vllm-project/vllm vulncheck.com: https://www.vulncheck.com/advisories/vllm-through-0.29.0-denial-of-service-via-nixl-multi-prompt-assertion-failure

Credits

Mingkai Yu Jiapeng Li Jiajia Liu