CVE-2026-115911

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.

• github.comhttps://github.com/vllm-project/vllm/commit/cff08b461e086523cee8bba5bd3c66d302625134
• github.comhttps://github.com/vllm-project/vllm/pull/50300
• github.comhttps://github.com/vllm-project/vllm/releases/tag/v0.32.0
• github.comhttps://github.com/vllm-project/vllm/security/advisories/GHSA-542m-9234-8gvf