Medium 6.5Published Nov 20, 2025

CVE-2025-62426vLLM vulnerable to DoS via large Chat Completion or Tokenization requests with specially crafted `chat_template_kwargs`

Updated under an hour ago (Oct 28, 2026, 7:40 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for vllm-project vllm

Exploited in the last 30 days

vLLM is an inference and serving engine for large language models (LLMs). From version 0.5.5 to before 0.11.1, the /v1/chat/completions and /tokenize endpoints allow a chat_template_kwargs request parameter that is used in the code before it is properly validated against the chat template. With the right chat_template_kwargs parameters, it is possible to block processing of the API server for long periods of time, delaying all other requests. This issue has been patched in version 0.11.1.

CVSS: 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-770
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Nov 24, 2025
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

vllm-project vllm vllm_project:vllm (from the name)	from 0.5.5, < 0.11.1	CNA record
vllm vllm vllm:vllm	from 0.5.5 before 0.11.1; 0.11.1; 0.11.1	NVD

References

References

https://github.com/vllm-project/vllm/security/advisories/GHSA-69j4-grxj-j64p	x-refsource-confirm, vendor-advisory
https://github.com/vllm-project/vllm/pull/27205	x-refsource-misc, issue-tracking
https://github.com/vllm-project/vllm/commit/3ada34f9cb4d1af763fdfa3b481862a93eb6bd2b	x-refsource-misc, patch
https://github.com/vllm-project/vllm/blob/2a6dc67eb520ddb9c4138d8b35ed6fe6226997fb/vllm/entrypoints/chat_utils.py#L1602-L1610	x-refsource-misc, product
https://github.com/vllm-project/vllm/blob/2a6dc67eb520ddb9c4138d8b35ed6fe6226997fb/vllm/entrypoints/openai/serving_engine.py#L809-L814	x-refsource-misc, product

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.