{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:pillarjs:path-to-regexp:*:*:*:*:*:node.js:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "0.1.13"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "9fd0c879f232c2464591f56dd7c7edad7f45b4e0"
            }
          ],
          "repo": "https://github.com/pillarjs/path-to-regexp",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-9wv6-86v2-598j"
  ],
  "database_specific": {
    "cna_assigner": "openjs",
    "cwe_ids": [
      "CWE-1333"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/4xxx/CVE-2026-4867.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "fixed": "0.1.13"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "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.",
  "id": "CVE-2026-4867",
  "modified": "2026-07-15T01:48:49.500361337Z",
  "published": "2026-03-26T16:16:25.501Z",
  "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"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "path-to-regexp vulnerable to Regular Expression Denial of Service via multiple route parameters"
}