{"cve":"CVE-2026-55574","nvd":{"published":"2026-07-06T21:16:57.347","modified":"2026-10-25T20:10:00.147","status":"Analyzed","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.","cvss_v4":{"vector":"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","score":8.7},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-1333"],"references":["https://github.com/vllm-project/vllm/commit/2b3006076c5e9bc4cda9e03e3641388de3c5c286","https://github.com/vllm-project/vllm/pull/45118","https://github.com/vllm-project/vllm/security/advisories/GHSA-rwxx-mrjm-wc2m"],"products":["vllm:vllm"],"source":"nvd","synced_at":"2026-10-25T23:44:34.550481224+00:00"},"epss":{"cve":"CVE-2026-55574","score":0.00583,"percentile":0.47592,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-rwxx-mrjm-wc2m","url":"https://osv.dev/vulnerability/GHSA-rwxx-mrjm-wc2m","summary":"vLLM: ReDoS via structured_outputs.regex compiled without timeout in xgrammar and outlines backends","modified":"2026-09-10T03:51:12.174615800Z","packages":[{"ecosystem":"PyPI","name":"vllm","purl":"pkg:pypi/vllm","ranges":["<0.24.0"],"fixed":["0.24.0"]}]},{"id":"PYSEC-2026-2304","url":"https://osv.dev/vulnerability/PYSEC-2026-2304","summary":"","modified":"2026-07-13T07:15:46.675101580Z","packages":[{"ecosystem":"PyPI","name":"vllm","purl":"pkg:pypi/vllm","ranges":["<0.24.0"],"fixed":["0.24.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}