CVE-2026-115911

01/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.

02/Affected products

vllm: vllm

03/References4

• github.com/vllm-project/vllm/security/advisories/GHSA-542m-9234… PatchVendor Advisory
• github.com/vllm-project/vllm/commit/cff08b461e086523cee8bba5bd3… Patch
• github.com/vllm-project/vllm/pull/50300 Patch
• github.com/vllm-project/vllm/releases/tag/v0.32.0 Release Notes