{"id":"CVE-2026-4923","aliases":["GHSA-27v5-c462-wpq7"],"url":"https://o3.security/vulnerability/CVE-2026-4923","summary":"path-to-regexp vulnerable to Regular Expression Denial of Service via multiple wildcards","details":"### Impact\n\nWhen using multiple wildcards, combined with at least one parameter, a regular expression can be generated that is vulnerable to ReDoS. This backtracking vulnerability requires the second wildcard to be somewhere other than the end of the path.\n\n**Unsafe examples:**\n\n```\n/*foo-*bar-:baz\n/*a-:b-*c-:d\n/x/*a-:b/*c/y\n```\n\n**Safe examples:**\n\n```\n/*foo-:bar\n/*foo-:bar-*baz\n```\n\n### Patches\n\nUpgrade to version `8.4.0`.\n\n### Workarounds\n\nIf developers are using multiple wildcard parameters, they can check the regex output with a tool such as https://makenowjust-labs.github.io/recheck/playground/ to confirm whether a path is vulnerable.","published":"2026-03-26T19:02:00.729Z","modified":"2026-08-12T03:51:42.091282062Z","cvss":{"score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.00353,"percentile":0.28856,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"path-to-regexp","fixedVersion":"8.4.0"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://cna.openjsf.org/security-advisories.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/4xxx/CVE-2026-4923.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-4923"},{"type":"WEB","url":"https://github.com/pillarjs/path-to-regexp/security/advisories/GHSA-27v5-c462-wpq7"},{"type":"PACKAGE","url":"https://github.com/pillarjs/path-to-regexp"},{"type":"WEB","url":"https://makenowjust-labs.github.io/recheck/playground"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:42.091282062Z"}}