{"schema_version":"1.7.5","id":"GHSA-j3q9-mxjg-w52f","published":"2026-03-27T22:23:27Z","modified":"2026-03-30T23:29:19.093657Z","aliases":["CVE-2026-4926"],"related":["CGA-4rwm-wmf3-xv3m"],"summary":"path-to-regexp vulnerable to Denial of Service via sequential optional groups","details":"### Impact\n\nA bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as `{a}{b}{c}:z`. The generated regex grows exponentially with the number of groups, causing denial of service.\n\n### Patches\n\nFixed in version 8.4.0.\n\n### Workarounds\n\nLimit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.","affected":[{"package":{"name":"path-to-regexp","ecosystem":"npm","purl":"pkg:npm/path-to-regexp"},"ranges":[{"type":"SEMVER","events":[{"introduced":"8.0.0"},{"fixed":"8.4.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-j3q9-mxjg-w52f/GHSA-j3q9-mxjg-w52f.json"}}],"references":[{"type":"WEB","url":"https://github.com/pillarjs/path-to-regexp/security/advisories/GHSA-j3q9-mxjg-w52f"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-4926"},{"type":"WEB","url":"https://cna.openjsf.org/security-advisories.html"},{"type":"PACKAGE","url":"https://github.com/pillarjs/path-to-regexp"}],"database_specific":{"cwe_ids":["CWE-1333","CWE-400"],"github_reviewed":true,"github_reviewed_at":"2026-03-27T22:23:27Z","nvd_published_at":"2026-03-26T19:17:08Z","severity":"HIGH"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}