{"id":"CVE-2026-94623","published":"2026-09-21T22:17:01.123","lastModified":"2026-09-22T20:25:55.870","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 vLLM library has a denial of service vulnerability in its NIXL connector's prefix caching implementation that fails to properly validate block counts when handling multiple prompts in prefill/decode deployments, leading to assertion failures and worker termination.","exploitability":"Exploitation is relatively straightforward as attackers only need to submit completion requests with multiple prompts of varying lengths to trigger the assertion failure in the NixlBaseConnectorWorker._apply_prefix_caching method.","blast_radius":"If exploited, this vulnerability could cause decode workers to terminate and become unavailable until restarted, potentially disrupting service availability for all users relying on the affected vLLM deployment.","remediation":"Upgrade to vLLM version 0.29.1 or later to address this denial of service vulnerability in the NIXL connector's prefix caching implementation.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["denial-of-service","llm","api"],"model":"garnet-coder","analyzedAt":"2026-10-18T16:15:57.882Z"}}