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GHSA-27V5-C462-WPQ7

Vulnerability from github – Published: 2026-03-27 22:23 – Updated: 2026-03-27 22:23
VLAI
Summary
path-to-regexp vulnerable to Regular Expression Denial of Service via multiple wildcards
Details

Impact

When 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.

Unsafe examples:

/*foo-*bar-:baz
/*a-:b-*c-:d
/x/*a-:b/*c/y

Safe examples:

/*foo-:bar
/*foo-:bar-*baz

Patches

Upgrade to version 8.4.0.

Workarounds

If 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.

Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "path-to-regexp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0"
            },
            {
              "fixed": "8.4.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-4923"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1333"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-27T22:23:52Z",
    "nvd_published_at": "2026-03-26T19:17:08Z",
    "severity": "MODERATE"
  },
  "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.",
  "id": "GHSA-27v5-c462-wpq7",
  "modified": "2026-03-27T22:23:52Z",
  "published": "2026-03-27T22:23:52Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pillarjs/path-to-regexp/security/advisories/GHSA-27v5-c462-wpq7"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-4923"
    },
    {
      "type": "WEB",
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pillarjs/path-to-regexp"
    },
    {
      "type": "WEB",
      "url": "https://makenowjust-labs.github.io/recheck/playground"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/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 wildcards"
}



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