CVE-2026-100647

Medium

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.

SeverityMedium

CVSS5.3

Exploit probability—

ProductVllm

PublishedSep 26, 2026

First seenSep 26, 2026

Weakness typeCWE-20Improper input validation

How to fix

Update

vllm vllm0.29.0 or later

Vendor advisories

github.com/vllm-project/vllm/security/advisories/GHSA-wpww-v874-ph2p

Affected products

Product	Affected versions	Fixed in
vllm vllm	v < 0.29.0	0.29.0

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