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CVE-2025-62426

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

Published: Nov 21, 2025Updated: Dec 4, 2025 Sources: CVE List NVD GHSA BDUCWE-770
6.5MEDIUM
NVD MITRE
EPSS Score
0.4%
Top 71.6%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Not available

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-770

Affected Products

vllm-project
oss-projectaka vllm, vllm-project/vllm
vllmMixed
AI / ML / llm-serving-inference
vllm
oss-projectaka aibrix
vllmMixed
AI / ML / llm-serving-inference
vLLM Project
oss-projectaka vllm
vLLMMixed
AI / ML / llm-serving-inference
PyPI
package-ecosystem
vllm
OSS Libraries

Exploitability

Official Patch Available

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://github.com/vllm-project/vllm/security/advisories/GHSA-69j4-grxj-j64p
github.com
https://github.com/vllm-project/vllm/pull/27205
github.com
https://github.com/vllm-project/vllm/commit/3ada34f9cb4d1af763fdfa3b481862a93eb6bd2b
github.com
and 9 more references View all →

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