Description
vLLM versions through 0.29.0 contain a denial of service vulnerability in the NIXL connector's metadata handling for prefill/decode disaggregated deployments. Attackers can send requests with incomplete kv_transfer_params dictionary entries to trigger an uncaught KeyError in EngineCore scheduling, causing the decode engine to terminate and making all routed requests fail until manual restart.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| vllm-project | vllm | ≤ 0.29.0 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | vllm | < 0.30.0 | 0.30.0 | PYSEC-2026-4004 |
Advisories 1
- WID-SEC-2026-3507 vllm: Mehrere Schwachstellen ermöglichen Denial of Service BSI CERT-Bund (WID) · Nov 9, 2026
References
- Pull Request #54807 issue-tracking patch
- https://github.com/vllm-project/vllm/blob/v0.29.0/vllm/distributed/kv_transfer/kv_connector/v1/nixl/metadata.py#L294-L312 technical-description
- https://github.com/vllm-project/vllm product
- VulnCheck Advisory: vLLM through 0.29.0 Denial of Service via Incomplete NIXL KV Transfer Metadata third-party-advisory