{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:pillarjs:path-to-regexp:*:*:*:*:*:node.js:*:*",
            "extracted_events": [
              {
                "introduced": "8.0.0"
              },
              {
                "fixed": "8.4.0"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "ed1095e0fa78a692e7f3d489e383e7bb1f9d2cc4"
            },
            {
              "fixed": "34cb451ddaeea4783a2fe60579ffb3e4ccfc73a7"
            }
          ],
          "repo": "https://github.com/pillarjs/path-to-regexp",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "openjs",
    "cwe_ids": [
      "CWE-1333",
      "CWE-400"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/4xxx/CVE-2026-4926.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "8.0.0"
          },
          {
            "fixed": "8.4.0"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "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\nPatches:\n\nFixed in version 8.4.0.\n\nWorkarounds:\n\nLimit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.",
  "id": "CVE-2026-4926",
  "modified": "2026-07-11T03:53:32.284850205Z",
  "published": "2026-03-26T18:59:38Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4926.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:10153"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:10172"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:10175"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:13545"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:13826"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:17789"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:19409"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:19410"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:24761"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:24762"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:24866"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:36651"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:9385"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:9742"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/security/cve/CVE-2026-4926"
    },
    {
      "type": "ADVISORY",
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/4xxx/CVE-2026-4926.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-4926"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2451867"
    }
  ],
  "schema_version": "1.7.5",
  "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 Denial of Service via sequential optional groups"
}