CVE-2026-94623
vLLM through 0.29.0 Denial of Service via NIXL Multi-Prompt Assertion Failure
- State
- Published
- Severity
- 8.7 High
- Published
- Sep 21, 2026
- Updated
- Sep 22, 2026
- Reserved
- Sep 21, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | VulnCheck |
Weaknesses
- CWE-617 Reachable Assertion
Affected Products
| Product | Versions |
|---|---|
vllmvllm-project |
|
References
- Pull Request #51505issue-trackingpatch
- https://github.com/vllm-project/vllm/blob/v0.29.0/vllm/distributed/kv_transfer/kv_connector/v1/nixl/base_worker.py#L2642-L2646technical-description
- https://github.com/vllm-project/vllmproduct
- VulnCheck Advisory: vLLM through 0.29.0 Denial of Service via NIXL Multi-Prompt Assertion Failurethird-party-advisory
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