{"id":"CVE-2026-4867","summary":"path-to-regexp vulnerable to Regular Expression Denial of Service via multiple route parameters","details":"Impact:\n\nA bad regular expression is generated any time you have three or more parameters within a single segment, separated by something that is not a period (.). For example, /:a-:b-:c or /:a-:b-:c-:d. The backtrack protection added in path-to-regexp@0.1.12 only prevents ambiguity for two parameters. With three or more, the generated lookahead does not block single separator characters, so capture groups overlap and cause catastrophic backtracking.\n\nPatches:\n\nUpgrade to path-to-regexp@0.1.13\n\nCustom regex patterns in route definitions (e.g., /:a-:b([^-/]+)-:c([^-/]+)) are not affected because they override the default capture group.\n\nWorkarounds:\n\nAll versions can be patched by providing a custom regular expression for parameters after the first in a single segment. As long as the custom regular expression does not match the text before the parameter, you will be safe. For example, change /:a-:b-:c to /:a-:b([^-/]+)-:c([^-/]+).\n\nIf paths cannot be rewritten and versions cannot be upgraded, another alternative is to limit the URL length.","aliases":["CVE-2024-45296","GHSA-37ch-88jc-xwx2","GHSA-9wv6-86v2-598j"],"modified":"2026-06-26T03:54:29.911303172Z","published":"2026-03-26T16:16:25.501Z","related":["CGA-8j86-34gg-44ch"],"database_specific":{"unresolved_ranges":[{"source":"AFFECTED_FIELD","extracted_events":[{"fixed":"0.1.13"}]}],"cna_assigner":"openjs","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/4xxx/CVE-2026-4867.json","cwe_ids":["CWE-1333"]},"references":[{"type":"WEB","url":"https://blakeembrey.com/posts/2024-09-web-redos"},{"type":"ADVISORY","url":"https://cna.openjsf.org/security-advisories.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/4xxx/CVE-2026-4867.json"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-9wv6-86v2-598j"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-4867"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/pillarjs/path-to-regexp","events":[{"introduced":"0"},{"fixed":"9fd0c879f232c2464591f56dd7c7edad7f45b4e0"}],"database_specific":{"source":"CPE_RANGE","cpe":"cpe:2.3:a:pillarjs:path-to-regexp:*:*:*:*:*:node.js:*:*","extracted_events":[{"introduced":"0"},{"fixed":"0.1.13"}]}}],"versions":["v0.1.12","v0.1.11","v0.1.10","v0.1.9","v0.1.8","v0.1.7","v0.1.6","v0.1.5","v0.1.4","v0.1.3","v0.1.2","v0.1.1","0.1.0","0.0.2"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-4867.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}