CVE catalog

CVE-2026-34756

vLLM is an inference and serving engine for large language models (LLMs). From 0.1.0 to before 0.19.0, a Denial of Service vulnerability exists in the vLLM OpenAI-compatible API server. Due to the lac

[CVE catalog]

Severity
Medium · CVSS 6.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Published
Source
[NVD] · [CVE record]
EPSS
0.42% · Oct 25, 2026

A flaw was found in vLLM, an inference and serving engine for large language models (LLMs). An unauthenticated attacker can exploit this vulnerability by sending a specially crafted HTTP request with an excessively large 'n' parameter to the vLLM OpenAI-compatible API server. This can lead to a Denial of Service (DoS) by consuming excessive memory and blocking the system's event loop, causing the server to crash. vllm: vLLM: Denial of Service via excessively large 'n' parameter in OpenAI-compatible API The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

DistributionPackageReleaseVersionStatus
CpevllmNot reported0.19.0fixed
CpevllmNot reported0.19.0fixed

Fixed-version evidence

DistributionPackageTypeReleaseFixed versionUrgencyOriginBugs
CpevllmcpeNot reported0.19.0Not reportedNot reportedNot reported
CpevllmcpeNot reported0.19.0Not reportedNVD-CVE-2026-34756Not reported

OpenFactory catalog packages

No matching packages in this catalog.

Observed:

References

[CERT-Bund public advisories] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [Red Hat security advisories and VEX]