CVEvulnerability
CVE-2026-55574
8.7 HIGH
Official page ↗
- Status
- Analyzed
- Published
- 2026-07-06
- Last modified
- 2026-10-25
- Assigner
- [email protected]
- CVSS 4.0 ([email protected])
- 8.7 HIGH — CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- CVSS 3.1 ([email protected])
- 7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weaknesses
- CWE-1333
Description
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.
Affected configurations
• vllm vllm (< 0.24.0)
Related
Weakness · CWE (1)
- CWE-1333 Inefficient Regular Expression Complexity weakness
References
- 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