CVE-2026-55574 vLLM: ReDoS via structured_outputs.regex compiled without timeout in xgrammar and outlines backends

vLLM is a high-throughput and memory-efficient inference and serving engine for LLMs. Prior to 0.24.0, the structuredoutputs.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 stri...

PT-2026-56000

Name of the Vulnerable Software and Affected Versions vLLM versions prior to 0.24.0 Description The structured outputs.regex API parameter allows user-supplied regular expression strings to be passed to grammar compiler backends without a compilation timeout. In the xgrammar backend, the string i...