CVE-2026-93840: Validation flaw in vLLM allowed_token_ids handling
vLLM
vLLM before 0.29.0 improperly validates allowed token IDs against tokenizer length instead of output logits width. Attackers can supply out-of-vocabulary tokens that corrupt GPU logits state and affect concurrent requests.
disclosed CVENo confirmed exploitation, so this record is tracked as a disclosed vulnerability and not counted as an incident. It moves into the counts if CISA or the vendor confirms exploitation. Why
- CVSS
- 6.3
- EPSS
- <0.01 · top 84% · 2026-11-13
- fix status
- Fix status unknown
- first report
- 18 Sep 2026
- last update
- 18 Sep 2026
- CVE ids
Timeline · 1
Sources · 1
Advisories and databases
- 2026-09-18CVE-2026-93840: vLLM before 0.29.0 validates allowed_token_ids against tokenizer length instead of model output logits width in…NVD · nvd.nist.gov/vuln/detail/CVE-2026-93840
Titles and links belong to their publishers. The summary above is written by gcdRadar in its own words; data is CC BY-SA 4.0.
Classification
- lane
- Patch now
- AI role
- Attack on AI
- categories
- Infrastructure vulnerability
- severity
- 2 · Disclosed vulnerability
- fix status
- Fix status unknown
- targets
- Framework / tooling
- owasp llm top 10
- LLM03:2025 Supply Chain
- mitre atlas
- no technique for these categories
- dates
- happened 18 Sep 2026 · first reported 18 Sep 2026
- origin
- NVDVulnerability record from NVD / the GitHub Advisory Database. This product uses the NVD API but is not endorsed or certified by the NVD.
- record
- confidence 0.95 · created 2026-10-18 06:33Z · updated 2026-10-18 06:33Z
Lane, AI role, categories and severity come from the classifier; the OWASP and ATLAS rows are derived from the categories. How these are assigned
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the brief as text
# CVE-2026-93840: Validation flaw in vLLM allowed_token_ids handling https://gcdradar.vercel.app/incidents/cve-2026-93840-validation-flaw-in-vllm-allowed-token-ids-han · AIR-2026-0151 · closed 2026-09-18 - Lane: Patch now - Severity: 2 (Disclosed vulnerability) - Fix status: Fix status unknown - First reported: 2026-09-18 - AI role: Attack on AI - Products: vLLM - CVE ids: CVE-2026-93840 - CVSS: 6.3 ## Summary vLLM before 0.29.0 improperly validates allowed token IDs against tokenizer length instead of output logits width. Attackers can supply out-of-vocabulary tokens that corrupt GPU logits state and affect concurrent requests. ## What to do No action recorded; read the sources below and the vendor's advisory. ## Latest updates - 2026-09-18: CVE-2026-93840: vLLM before 0.29.0 validates allowed_token_ids against tokenizer length instead of model output logits width in… (https://nvd.nist.gov/vuln/detail/CVE-2026-93840) ## Sources - 2026-09-18 NVD: CVE-2026-93840: vLLM before 0.29.0 validates allowed_token_ids against tokenizer length instead of model output logits width in… https://nvd.nist.gov/vuln/detail/CVE-2026-93840 Verify against the vendor's advisory before changing production. Data CC BY-SA 4.0, https://gcdradar.vercel.app.
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