Vulnerability-Lookup

CVE-2026-4926 (GCVE-0-2026-4926)

Vulnerability from cvelistv5 – Published: 2026-03-26 18:59 – Updated: 2026-03-27 19:44

Title

path-to-regexp vulnerable to Denial of Service via sequential optional groups

Summary

Impact: A 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. Patches: Fixed in version 8.4.0. Workarounds: Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

Severity ?

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE

CWE-400 - Uncontrolled Resource Consumption
CWE-1333 - Inefficient Regular Expression Complexity

Assigner

openjs

References

URL

Tags

https://cna.openjsf.org/security-advisories.html

Impacted products

	Vendor	Product	Version
	path-to-regexp	path-to-regexp	Affected: 8.0.0 , < 8.4.0 (semver) Unaffected: 8.4.0 (semver)

Credits

uug4na blakeembrey UlisesGascon

Show details on NVD website

JSON

To clipboard

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GHSA-J3Q9-MXJG-W52F

Vulnerability from github – Published: 2026-03-27 22:23 – Updated: 2026-03-27 22:23

Summary

path-to-regexp vulnerable to Denial of Service via sequential optional groups

Details

Impact

A 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.

Patches

Fixed in version 8.4.0.

Workarounds

Limit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.

Severity ?

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "path-to-regexp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0"
            },
            {
              "fixed": "8.4.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-4926"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1333",
      "CWE-400"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-27T22:23:27Z",
    "nvd_published_at": "2026-03-26T19:17:08Z",
    "severity": "HIGH"
  },
  "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\n### Patches\n\nFixed in version 8.4.0.\n\n### Workarounds\n\nLimit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.",
  "id": "GHSA-j3q9-mxjg-w52f",
  "modified": "2026-03-27T22:23:27Z",
  "published": "2026-03-27T22:23:27Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pillarjs/path-to-regexp/security/advisories/GHSA-j3q9-mxjg-w52f"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-4926"
    },
    {
      "type": "WEB",
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pillarjs/path-to-regexp"
    }
  ],
  "schema_version": "1.4.0",
  "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 Denial of Service via sequential optional groups"
}

FKIE_CVE-2026-4926

Vulnerability from fkie_nvd - Published: 2026-03-26 19:17 - Updated: 2026-03-30 13:26

Severity ?

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Summary

References

	URL	Tags
	ce714d77-add3-4f53-aff5-83d477b104bb	https://cna.openjsf.org/security-advisories.html

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    },
    {
      "lang": "es",
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    }
  ],
  "id": "CVE-2026-4926",
  "lastModified": "2026-03-30T13:26:50.827",
  "metrics": {
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          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
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  "published": "2026-03-26T19:17:08.387",
  "references": [
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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.

Detection rules are retrieved from Rulezet.

Action not permitted

CVE-2026-4926 (GCVE-0-2026-4926)

GHSA-J3Q9-MXJG-W52F

Impact

Patches

Workarounds

FKIE_CVE-2026-4926

Tags

Sightings

Nomenclature