vLLM is a high-throughput and memory-efficient inference and serving engine for LLMs. Prior to 0.24.0, the structured_outputs.regex API parameter passes a user-supplied regular expression string directly to the grammar compiler backends with no compilation timeout; in the xgrammar backend the string reaches the regex compiler with no guard, and in the outlines backend the validation step blocks structural issues such as lookarounds and backreferences but performs no complexity analysis, so a pattern with nested quantifiers passes all checks and causes exponential state-space expansion, allowing a single request containing an adversarial regex to hang an inference worker indefinitely and deny service. This issue is fixed in version 0.24.0.
Fix
Patch, vendor advisory and mitigation references on NVD 3
- https://github.com/vllm-project/vllm/commit/2b3006076c5e9bc4cda9e03e3641388de3c5c286 Patch
- https://github.com/vllm-project/vllm/pull/45118 Issue Tracking, Patch
- https://github.com/vllm-project/vllm/security/advisories/GHSA-rwxx-mrjm-wc2m Vendor Advisory, Mitigation
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 8.7 · vllmNVD modified 2026-10-25 20:10
Affected (CPE criteria) 1
cpe:2.3:a:vllm:vllm:*:*:*:*:*:*:*:*
References 3
- https://github.com/vllm-project/vllm/commit/2b3006076c5e9bc4cda9e03e3641388de3c5c286 Patch
- https://github.com/vllm-project/vllm/pull/45118 Issue Tracking, Patch
- https://github.com/vllm-project/vllm/security/advisories/GHSA-rwxx-mrjm-wc2m Vendor Advisory, Mitigation