CVE-2026-93989

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.

  • Published Sep 19, 2026
  • CVSS 2.3 low
  • 0.2% chance of exploitation in the next 30 days (EPSS)
  • A fix is available

Affected software

CVE-2026-93989 at the National Vulnerability Database