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.

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact Low

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable yes

Technical Impact partial

Affected Vendors & Products

Vendors Products
Vllm
  • Vllm

Configuration 1 [-]

cpe:2.3:a:vllm:vllm:*:*:*:*:*:*:*:*

No data.

References
Link Providers
https://github.com/vllm-project/vllm/security/advisories/GHSA-wpww-v874-ph2p cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-100647 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-100647 cve-icon
https://www.vulncheck.com/advisories/vllm-before-0.29.0-cpu-exhaustion-via-unbounded-cache-salt cve-icon cve-icon cve-icon
History

Mon, 28 Sep 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Sun, 27 Sep 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-1322
References
Metrics threat_severity

None

 threat_severity

Moderate

Sat, 26 Sep 2026 13:30:00 +0000

Type Values Removed Values Added
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.
Title vLLM before 0.29.0 CPU Exhaustion via unbounded cache_salt
First Time appeared Vllm
Vllm vllm
Weaknesses CWE-20
CPEs cpe:2.3:a:vllm:vllm:*:*:*:*:*:*:*:*
Vendors & Products Vllm
Vllm vllm
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published: 2026-09-26T13:23:18.240Z

Updated: 2026-09-28T18:28:14.772Z

Reserved: 2026-09-26T02:33:07.898Z

Link: CVE-2026-100647

cve-icon Vulnrichment

Updated: 2026-09-28T18:28:05.355Z

cve-icon NVD

Status : Analyzed

Published: 2026-09-26T14:16:47.097

Modified: 2026-10-06T19:46:06.527

Link: CVE-2026-100647

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-09-26T13:23:18Z

Links: CVE-2026-100647 - Bugzilla