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CVE-2026-105756— vLLM: Loose `cache_salt` validation lets a single request kill EngineCore on LMCache-MP deployments — uncaught downstream `ValueError` denial of service

Quick assessment

Affected
vllm-project vllm
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

vLLM 是一个用于大语言模型的推理和服务引擎。在 0.30.0 版本之前，兼容 OpenAI 的请求模型接受非空的 cache_salt 值，而未强制执行 LMCache-MP 中 IPCCacheServerKey 消费者所要求的字符和长度限制。在使用 LMCache-MP 连接器部署的环境中，包含非法字符或超出允许长度的 salt 可能导致在调度器缓存查找期间引发未捕获的 ValueError 异常，进而导致 EngineCore 终止，并向所有并发用户拒绝服务。此问题已在 0.30.0 版本中修复。

CVSS 6.5 · Medium
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I. Basic Information for CVE-2026-105756

Vulnerability Information
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Vulnerability Title
vLLM: Loose `cache_salt` validation lets a single request kill EngineCore on LMCache-MP deployments — uncaught downstream `ValueError` denial of service
Source: CVE Program / CVE List V5
Vulnerability Description
vLLM is an inference and serving engine for large language models. Prior to 0.30.0, OpenAI-compatible request models accept a non-empty cache_salt value without enforcing the character and length restrictions required by the IPCCacheServerKey consumer in LMCache-MP. On deployments using the LMCache-MP connector, a salt that contains a forbidden character or exceeds the permitted length can raise an uncaught ValueError during scheduler cache lookup, causing EngineCore to terminate and denying service to all concurrent users. This issue is fixed in version 0.30.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
输入验证不恰当
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
vllm-project vllm < 0.30.0 -

II. Public POCs for CVE-2026-105756

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III. Intelligence Information for CVE-2026-105756

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Other References for CVE-2026-105756 (4)

Same Patch Batch · vllm-project · 2026-10-05 · 9 CVEs total

CVE-2026-105753 6.5 MEDIUM vLLM: Mirrored multimodal IPC caches desync after a rejected request — a later request reu
CVE-2026-105754 6.5 MEDIUM vLLM: Scale-out disaggregated multimodal transport trusts caller-supplied features
CVE-2026-105757 6.5 MEDIUM vLLM: Structured-output request errors escape the request boundary and terminate the share
CVE-2026-105759 5.9 MEDIUM vLLM: Unbounded Prometheus label cardinality from attacker-controlled HTTP method tokens i
CVE-2026-105760 5.3 MEDIUM vLLM: GLMGA video sampling permits request-driven CPU and memory exhaustion
CVE-2026-105758 5.3 MEDIUM vLLM: Qwen2-VL / Qwen3-VL video samplers bound on request-controlled max_frames, which the
CVE-2026-105755 4.2 MEDIUM vLLM: Flash late-interaction scoring caches query embeddings under a caller-controlled req
CVE-2026-105752 3.1 LOW vLLM: Harmony tool continuations drop `cache_salt` — restoring a cross-tenant prefix-cache

IV. Related Vulnerabilities

Same product: vllm
Same vendor: vllm-project
Same weakness: CWE-20

V. Comments for CVE-2026-105756

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