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)
{
"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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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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