{"id":"CVE-2026-94623","published":"2026-09-21T22:17:01.123","lastModified":"2026-09-21T22:17:01.123","description":"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.","cvssScore":7.5,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwes":["CWE-617"],"vendors":[],"products":[],"references":[{"url":"https://github.com/vllm-project/vllm","tags":[]},{"url":"https://github.com/vllm-project/vllm/blob/v0.29.0/vllm/distributed/kv_transfer/kv_connector/v1/nixl/base_worker.py#L2642-L2646","tags":[]},{"url":"https://github.com/vllm-project/vllm/pull/51505","tags":[]},{"url":"https://www.vulncheck.com/advisories/vllm-through-0.29.0-denial-of-service-via-nixl-multi-prompt-assertion-failure","tags":[]}],"exploitRefs":[{"url":"https://github.com/vllm-project/vllm","tags":[]},{"url":"https://github.com/vllm-project/vllm/blob/v0.29.0/vllm/distributed/kv_transfer/kv_connector/v1/nixl/base_worker.py#L2642-L2646","tags":[]},{"url":"https://github.com/vllm-project/vllm/pull/51505","tags":[]}],"hasPoc":true,"ai":{"summary":"The flaw allows attackers to trigger an assertion failure in vLLM's NIXL connector by submitting multi-prompt completion requests, leading to service disruption.","exploitability":"Exploitation requires sending specific crafted requests; preconditions include using a version of vLLM prior to 0.29.1 which addresses the issue.","blast_radius":"If exploited, it could cause the decode worker to terminate and become unavailable until restarted, impacting service availability.","remediation":"Update to vLLM version 0.29.1 or later to mitigate the vulnerability.","tags":["dos","service-disruption","update"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-09-22T06:14:56.485Z"}}