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CVE-2026-115918EUVD-2026-110039GHSA-X567-49G5-P4CFPYSEC-2026-4349

vLLM: Responses API bypasses trust_request_chat_template for chat_template_kwargs

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 0.32.0
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

vLLM, an open-source engine for serving large language models, is affected through its Responses API endpoint (/v1/responses). An authenticated user can supply their own chat template that bypasses the server's intended trust restrictions, causing the server to consume excessive CPU or memory during template rendering, which can degrade or disrupt service.

Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.

Read the original description

vLLM is an inference and serving engine for large language models. From 0.16.0 until 0.32.0, the /v1/responses endpoint allows an authenticated caller to place an attacker-controlled template in chat_template_kwargs[chat_template] when no server template is configured. ChatParams.get_apply_chat_template_kwargs() preserves that value without enforcing trust_request_chat_template, so the request can bypass the intended trust policy and cause CPU or memory exhaustion through Jinja rendering. This issue is fixed in version 0.32.0.

Timeline

  1. CVE published
  2. First seen by cve.now
  3. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  4. Record last updated

Affected versions

  • vllm-project vllm

    From 0.16.0 · fixed in 0.32.0

  • vllmPyPI

    From 0.16.0 · fixed in 0.32.0

References 4

GitHub · vllm-project/vllm