vLLM: ReDoS via structured_outputs.regex in the lm-format-enforcer backend (no compile timeout) — missed sibling of GHSA-rwxx-mrjm-wc2m

SummaryThe fix for GHSA-rwxx-mrjm-wc2m "ReDoS via structuredoutputs.regex compiled without timeout" wrapped the regex compile in the xgrammar and outlines backends with compileregexwithtimeout and, for outlines, validateregexisbuildable. The lm-format-enforcer backend was left unguarded: it...

PYSEC-2026-3933 vLLM: ReDoS via structured_outputs.regex in the lm-format-enforcer backend (no compile timeout) — missed sibling of GHSA-rwxx-mrjm-wc2m

Summary The fix for GHSA-rwxx-mrjm-wc2m "ReDoS via structuredoutputs.regex compiled without timeout" wrapped the regex compile in the xgrammar and outlines backends with compileregexwithtimeout and, for outlines, validateregexisbuildable. The lm-format-enforcer backend was left unguarded: it...

GHSA-48JH-3GJ7-FG8V vLLM: ReDoS via structured_outputs.regex in the lm-format-enforcer backend (no compile timeout) — missed sibling of GHSA-rwxx-mrjm-wc2m

Summary The fix for GHSA-rwxx-mrjm-wc2m "ReDoS via structuredoutputs.regex compiled without timeout" wrapped the regex compile in the xgrammar and outlines backends with compileregexwithtimeout and, for outlines, validateregexisbuildable. The lm-format-enforcer backend was left unguarded: it...

CVE-2026-73556 vLLM: ReDoS via structured_outputs.regex in the lm-format-enforcer backend (no compile timeout) — missed sibling of CVE-2026-55574

vLLM is an inference and serving engine for large language models. Prior to 0.26.0, the structuredoutputs.regex parameter in vllm/v1/structuredoutput/backendlmformatenforcer.py is passed to lmformatenforcer.RegexParser without compileregexwithtimeout or validation in...

PT-2026-71671

Name of the Vulnerable Software and Affected Versions vLLM versions prior to 0.26.0 Description An unauthenticated request to the '/v1/completions' endpoint can cause a denial of service by consuming a CPU core and stalling the structured-output engine path. This occurs because the structured...

EUVD-2026-41924

vLLM: ReDoS via structuredoutputs.regex compiled without timeout in xgrammar and outlines backends...

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...

CVE-2026-55574

A flaw was found in vLLM, a high-throughput and memory-efficient inference and serving engine for large language models LLMs. A remote attacker could exploit this vulnerability by providing a specially crafted regular expression to the structuredoutputs.regex API parameter. This adversarial regex...

PYSEC-2026-2304

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...

CVE-2026-55574

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...

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...

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...

CVE-2026-55574

CVE-2026-55574 affects vLLM prior to 0.24.0, where structured_outputs.regex passes an unguarded user-supplied regex to grammar backends (xgrammar and outlines). In xgrammar, the string reaches the regex compiler without a timeout guard; in outlines, validation overlooks regex complexity (e.g., ne...

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 or complexity analysis. In the xgramma...

Spring AI Embraces OpenAI's Structured Outputs: Enhancing JSON Response Reliability

OpenAI recently introduced a powerful feature called Structured Outputs, which ensures that AI-generated responses adhere strictly to a predefined JSON schema. This feature significantly improves the reliability and usability of AI-generated content in real-world applications. Today, we're excite...