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vLLM through 0.29.0 Cross-Request Logits Corruption via bad_words

Type: advisorySources: OSV

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.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-93989
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 18:36 UTC · Revision 1

Source evidence

vLLM through 0.29.0 Cross-Request Logits Corruption via bad_words

core-osv · Original source

Published 19 Sept 2026, 22:58 UTC

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.

osv:CVE-2026-93989
Complete source record
{
  "id": "a0e1d2cd77e0ab9b19c81ac538766a459db92f5cd729e006f86bae0102925755",
  "url": "https://osv.dev/vulnerability/CVE-2026-93989",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "vLLM through 0.29.0 Cross-Request Logits Corruption via bad_words",
    "summary": "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.",
    "evidence": "osv:CVE-2026-93989",
    "products": [],
    "severity": "low",
    "structured": {
      "id": "CVE-2026-93989",
      "aliases": [
        "CVE-2026-93989",
        "PYSEC-2026-4000"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/vllm-project/vllm",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "98dff2a81d747d1dba01a47f939f48c3526d4206"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "0.29.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "cpe": "cpe:2.3:a:vllm:vllm:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "0.29.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.29.0",
            "v0.29.0rc6",
            "v0.29.0rc5",
            "v0.29.0rc4",
            "v0.29.0rc3",
            "v0.29.0rc2",
            "v0.29.0rc1",
            "v0.28.1rc0",
            "v0.27.2rc0",
            "v0.26.1rc0",
            "v0.25.0",
            "v0.23.1rc0",
            "v0.22.1rc0",
            "v0.21.1rc0",
            "v0.20.2rc0",
            "v0.20.1rc0",
            "v0.19.2rc0",
            "v0.19.1rc0",
            "v0.18.2rc0",
            "v0.18.1rc0",
            "v0.17.2rc0",
            "v0.18.0rc0",
            "v0.17.1rc0",
            "v0.17.0rc0",
            "v0.16.0rc1",
            "v0.15.2rc0",
            "v0.16.0rc0",
            "v0.15.0rc1",
            "v0.14.0rc1",
            "v0.14.0rc0",
            "v0.13.0rc1",
            "v0.11.1",
            "v0.11.1rc6",
            "v0.11.1rc5",
            "v0.11.1rc4",
            "v0.11.1rc3",
            "v0.11.1rc2",
            "v0.11.1rc1",
            "v0.11.1rc0",
            "v0.11.0rc1",
            "v0.10.2rc2",
            "v0.10.2rc1",
            "v0.10.1rc1",
            "v0.10.0rc2",
            "v0.10.0",
            "v0.10.0rc1",
            "v0.9.2rc1",
            "v0.9.1rc2",
            "v0.9.1",
            "v0.9.1rc1",
            "v0.9.0",
            "v0.8.4",
            "v0.8.3rc1",
            "v0.8.2",
            "v0.8.1",
            "v0.8.0rc2",
            "v0.8.0rc1",
            "v0.7.3",
            "v0.7.2",
            "v0.7.1",
            "v0.7.0",
            "v0.6.6.post1",
            "v0.6.6",
            "v0.6.5",
            "v0.6.4.post1",
            "v0.6.4",
            "v0.6.3.post1",
            "v0.6.3",
            "v0.6.2",
            "v0.6.1.post2",
            "v0.6.1.post1",
            "v0.6.1",
            "v0.6.0",
            "v0.5.5",
            "v0.5.4",
            "v0.5.3.post1",
            "v0.5.3",
            "v0.5.2",
            "v0.5.1",
            "v0.5.0.post1",
            "v0.5.0",
            "v0.4.3",
            "v0.4.2",
            "v0.4.1",
            "v0.4.0.post1",
            "v0.4.0",
            "v0.3.3",
            "v0.3.2",
            "v0.3.1",
            "v0.3.0",
            "v0.2.7",
            "v0.2.6",
            "v0.2.5",
            "v0.2.4",
            "v0.2.3",
            "v0.2.2",
            "v0.2.1",
            "v0.2.0",
            "v0.1.7",
            "v0.1.6",
            "v0.1.5",
            "v0.1.4",
            "v0.1.3",
            "v0.1.2",
            "v0.1.1",
            "v0.1.0",
            "submission"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93989.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:38.408967277Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93989.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-93989",
        "https://www.vulncheck.com/advisories/vllm-through-0.29.0-cross-request-logits-corruption-via-bad-words",
        "https://github.com/vllm-project/vllm/pull/48824",
        "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"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-129"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93989.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-93989",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 505747,
  "published_at": "2026-09-19T22:58:10.572+00:00"
}