{"cve":"CVE-2026-73556","nvd":{"published":"2026-08-13T15:20:17.927","modified":"2026-09-28T18:42:04.937","status":"Analyzed","description":"vLLM is an inference and serving engine for large language models. Prior to 0.26.0, the structured_outputs.regex parameter in vllm/v1/structured_output/backend_lm_format_enforcer.py is passed to lmformatenforcer.RegexParser without compile_regex_with_timeout or validation in validate_structured_output_request_lm_format_enforcer, allowing an unauthenticated /v1/completions request against the lm-format-enforcer backend to consume a CPU core and stall the structured-output engine path with a catastrophic regular expression. This issue is fixed in version 0.26.0.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","score":5.3},"cwes":["CWE-400","CWE-1333"],"references":["https://github.com/vllm-project/vllm/commit/c9a788eedc412acceaa5112e0d44624b49841577","https://github.com/vllm-project/vllm/pull/47595","https://github.com/vllm-project/vllm/releases/tag/v0.26.0","https://github.com/vllm-project/vllm/security/advisories/GHSA-48jh-3gj7-fg8v","https://github.com/vllm-project/vllm/security/advisories/GHSA-48jh-3gj7-fg8v"],"products":["vllm:vllm"],"source":"nvd","synced_at":"2026-10-19T22:48:17.459049833+00:00"},"epss":{"cve":"CVE-2026-73556","score":0.00515,"percentile":0.43918,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-48jh-3gj7-fg8v","url":"https://osv.dev/vulnerability/GHSA-48jh-3gj7-fg8v","summary":"vLLM: ReDoS via structured_outputs.regex in the lm-format-enforcer backend (no compile timeout) — missed sibling of GHSA-rwxx-mrjm-wc2m","modified":"2026-09-10T12:25:34.716905199Z","packages":[{"ecosystem":"PyPI","name":"vllm","purl":"pkg:pypi/vllm","ranges":["<0.26.0"],"fixed":["0.26.0"]}]},{"id":"PYSEC-2026-3933","url":"https://osv.dev/vulnerability/PYSEC-2026-3933","summary":"vLLM: ReDoS via structured_outputs.regex in the lm-format-enforcer backend (no compile timeout) — missed sibling of GHSA-rwxx-mrjm-wc2m","modified":"2026-09-10T12:15:13.663911452Z","packages":[{"ecosystem":"PyPI","name":"vllm","purl":"pkg:pypi/vllm","ranges":["<0.26.0"],"fixed":["0.26.0"]}]}],"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."]}