| Component | vLLM |
| Severity | low (CVSS 3.1) |
| CVSS vector | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N |
| Published (NVD) | 2026-09-19 |
| Last modified | 2026-09-28 |
| Affected versions | vllm <= 0.29.0 |
| Fixed in | see the vendor advisory |
| Weakness | CWE-129 |
| CISA KEV | not listed |
NVD description
vLLM through 0.29.0 fails to properly validate bad_words token indices against the model's generation output width in SamplingParams.update_from_tokenizer(). Attackers can supply out-of-bounds token indices that corrupt logits memory of concurrent requests, causing different in-flight HTTP requests to return incorrect tokens.
What to do
- NVD lists no fixed version yet: follow the vendor advisory below and keep vLLM off the public internet until a fix ships.
- Do not expose the component's API or UI to the internet without authentication in front of it.
Sources
- NVD: CVE-2026-93989
- https://github.com/vllm-project/vllm/pull/48824
- https://www.vulncheck.com/advisories/vllm-through-0.29.0-cross-request-logits-corruption-via-bad-words
- https://github.com/vllm-project/vllm
- https://github.com/vllm-project/vllm/blob/98dff2a81d747d1dba01a47f939f48c3526d4206/vllm/sampling_params.py#L694-L753
- https://github.com/vllm-project/vllm/blob/98dff2a81d747d1dba01a47f939f48c3526d4206/vllm/v1/worker/gpu/sample/bad_words.py
Read more
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