GHSA-RWXX-MRJM-WC2M vLLM: ReDoS via structured_outputs.regex compiled without timeout in xgrammar and outlines backends

Summary The structuredoutputs.regex API parameter passes a user-supplied regex string directly to grammar compiler backends with no compilation timeout. In the xgrammar backend, the string reaches compileregex with no guard. In the outlines backend, validateregexisbuildable blocks structural issu...