vLLM is an inference and serving engine for large language models. From 0.19.0 until 0.32.0, authenticated callers can supply a request chat template when no server-side --chat-template is configured, or a malicious model repository can provide a template that is compiled and rendered by tokenizer.apply_chat_template() without a wall-clock timeout, output-size limit, or iteration bound. Rendering runs in a ThreadPoolExecutor with one worker by default, so a nonterminating render can block /v1/responses and other chat-template users after the request ends, while an output-expanding render can exhaust server memory. Harmony models are not affected because they do not use this Jinja path. This issue is fixed in version 0.32.0.
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Affected Vendors & Products
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Solution
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References
History
Mon, 26 Oct 2026 18:45:00 +0000
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Vllm
Vllm vllm Vllm-project Vllm-project vllm |
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Vllm
Vllm vllm Vllm-project Vllm-project vllm |
Mon, 26 Oct 2026 17:00:00 +0000
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| Description | vLLM is an inference and serving engine for large language models. From 0.19.0 until 0.32.0, authenticated callers can supply a request chat template when no server-side --chat-template is configured, or a malicious model repository can provide a template that is compiled and rendered by tokenizer.apply_chat_template() without a wall-clock timeout, output-size limit, or iteration bound. Rendering runs in a ThreadPoolExecutor with one worker by default, so a nonterminating render can block /v1/responses and other chat-template users after the request ends, while an output-expanding render can exhaust server memory. Harmony models are not affected because they do not use this Jinja path. This issue is fixed in version 0.32.0. | |
| Title | vLLM: DoS via unbounded chat_template Jinja2 rendering exhausts the renderer thread pool | |
| Weaknesses | CWE-400 CWE-770 CWE-834 |
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| References |
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| Metrics |
cvssV3_1
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-10-26T16:47:59.377Z
Reserved: 2026-10-23T20:21:45.107Z
Link: CVE-2026-115911
No data.
Status : Awaiting Analysis
Published: 2026-10-26T17:17:18.753
Modified: 2026-10-26T18:34:17.050
Link: CVE-2026-115911
No data.
OpenCVE Enrichment
Updated: 2026-10-26T18:30:14Z