vLLM before 0.29.0 CPU Exhaustion via unbounded cache_salt (CVE-2026-100647) | HOL Guard CVE

Medium · CVSS 6.9CVE-2026-100647

vLLM before 0.29.0 CPU Exhaustion via unbounded cache_salt

Answer in brief

CVE-2026-100647 records a Medium severity (CVSS 6.9) vulnerability in vLLM before 0.29.0 CPU Exhaustion via unbounded cache_salt. The current sources do not mark it as known exploited. The current feed maps vllm-project/vllm (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 26, 2026Updated Sep 26, 2026Source checked Sep 26, 2026First seen by HOL Sep 26, 2026Material review Sep 26, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.9
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 6.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps vllm-project/vllm (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
vllm-project/vllmgeneric	>=0 <0.29.0	0.29.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for vllm-project/vllm.
Review the reported fix. Update vllm-project/vllm to 0.29.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 26, 2026

Sources and claim methodology

Upstream source description

vLLM versions before 0.29.0 contain a denial-of-service vulnerability in the cache_salt parameter accepted on OpenAI-compatible and Anthropic API endpoints, which lacks maximum length validation and is processed on the single EngineCore scheduler thread. Unauthenticated attackers can send HTTP requests with multi-hundred-megabyte salt values that trigger expensive pickle serialization and SHA-256 hashing, stalling the scheduler thread and denying service to all concurrent requests.

Quoted source text, attributed separately from HOL analysis.