vLLM before 0.29.0 Cross-Request Logits Corruption via allowed_token_ids
Summary
| CVE | CVE-2026-93840 |
|---|---|
| State | PUBLISHED |
| Assigner | VulnCheck |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-18 20:17:34 UTC |
| Updated | 2026-09-28 18:36:00 UTC |
| Description | vLLM before 0.29.0 validates allowed_token_ids against tokenizer length instead of model output logits width in SamplingParams._validate_allowed_token_ids(). Attackers can supply token IDs above the output vocabulary that pass validation, causing LogitBiasState to corrupt GPU logits state and allow concurrent requests to sample tokens outside their allowlists. |
Risk And Classification
Primary CVSS: v4.0 6.3 MEDIUM from [email protected]
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS: 0.002460000 probability, percentile 0.142120000 (date 2026-09-29)
Problem Types: CWE-129 | CWE-129 Improper Validation of Array Index
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 6.3 | MEDIUM | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 6.3 | MEDIUM | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N |
| 3.1 | [email protected] | Primary | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| 3.1 | [email protected] | Secondary | 3.7 | LOW | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N |
| 3.1 | CNA | CVSS | 3.7 | LOW | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
PresentPrivileges Required
NoneUser Interaction
NoneConfidentiality
NoneIntegrity
LowAvailability
NoneSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
LowAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Vllm-project | Vllm | affected 0.29.0 semver | Not specified |
| CNA | Vllm-project | Vllm | unaffected 0.29.0 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/vllm-project/vllm/blob/v0.28.0/vllm/sampling_params.py | [email protected] | github.com | Product |
| github.com/vllm-project/vllm/pull/49080 | [email protected] | github.com | Issue Tracking, Patch |
| github.com/vllm-project/vllm/blob/v0.28.0/vllm/v1/worker/gpu/sample/logi... | [email protected] | github.com | Product |
| www.vulncheck.com/advisories/vllm-before-0.29.0-cross-request-logits-corruption... | [email protected] | www.vulncheck.com | Third Party Advisory |
| github.com/vllm-project/vllm | [email protected] | github.com | Product |
| github.com/vllm-project/vllm/commit/5b0e5b69ac1a3884a6479c9537789c95263c... | [email protected] | github.com | Patch |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Mingkai Yu (en)
CNA: Jiapeng Li (en)
CNA: Jiajia Liu (en)
There are currently no legacy QID mappings associated with this CVE.