Vulnerability in Vllm
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 · last modified .
CVSS v3 metric
CVSS v3 base score 3.1 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (10.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 10.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/vllm-project/vllm/pull/48824 (issue-tracking, Patch, patch, Issue Tracking)
- github.com/vllm-project/vllm/blob/98dff2a81d747d1dba01a47f939f48c3526d4206/vllm… (Product, technical-description)
- github.com/vllm-project/vllm/blob/98dff2a81d747d1dba01a47f939f48c3526d4206/vllm… (Product, technical-description)
- github.com/vllm-project/vllm (Product, product)
- www.vulncheck.com/advisories/vllm-through-0.29.0-cross-request-logits-corruptio… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-93989?
- CVE-2026-93989 is a low-severity vulnerability in Vllm, classified under Improper Validation of Array Index. CVSS score: 3.1/10. Published 2026-09-19.
- How severe is CVE-2026-93989?
- Low severity. CVSS v3 base score is 3.1 out of 10.