CVE-2026-4923 (GCVE-0-2026-4923)

Vulnerability from cvelistv5 – Published: 2026-03-26 19:02 – Updated: 2026-03-27 13:58
VLAI?
Title
path-to-regexp vulnerable to Regular Expression Denial of Service via multiple wildcards
Summary
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 you are using multiple wildcard parameters, you 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
CWE
  • CWE-1333 - Inefficient Regular Expression Complexity
Assigner
References
Impacted products
Vendor Product Version
path-to-regexp path-to-regexp Affected: 8.0.0 , < 8.4.0 (semver)
Unaffected: 8.4.0 (semver)
Create a notification for this product.
Credits
blakeembrey UlisesGascon
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-4923",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-27T13:46:47.360477Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-27T13:58:03.925Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:npm/path-to-regexp",
          "product": "path-to-regexp",
          "vendor": "path-to-regexp",
          "versions": [
            {
              "lessThan": "8.4.0",
              "status": "affected",
              "version": "8.0.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "8.4.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "blakeembrey"
        },
        {
          "lang": "en",
          "type": "remediation reviewer",
          "value": "UlisesGascon"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "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\nUnsafe examples:\n\n/*foo-*bar-:baz\n/*a-:b-*c-:d\n/x/*a-:b/*c/y\n\nSafe examples:\n\n/*foo-:bar\n/*foo-:bar-*baz\n\nPatches:\n\nUpgrade to version 8.4.0.\n\nWorkarounds:\n\nIf you are using multiple wildcard parameters, you can check the regex output with a tool such as https://makenowjust-labs.github.io/recheck/playground/ to confirm whether a path is vulnerable."
            }
          ],
          "value": "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\nUnsafe examples:\n\n/*foo-*bar-:baz\n/*a-:b-*c-:d\n/x/*a-:b/*c/y\n\nSafe examples:\n\n/*foo-:bar\n/*foo-:bar-*baz\n\nPatches:\n\nUpgrade to version 8.4.0.\n\nWorkarounds:\n\nIf you are using multiple wildcard parameters, you can check the regex output with a tool such as https://makenowjust-labs.github.io/recheck/playground/ to confirm whether a path is vulnerable."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 5.9,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-1333",
              "description": "CWE-1333: Inefficient Regular Expression Complexity",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-26T19:02:00.729Z",
        "orgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
        "shortName": "openjs"
      },
      "references": [
        {
          "url": "https://cna.openjsf.org/security-advisories.html"
        }
      ],
      "title": "path-to-regexp vulnerable to Regular Expression Denial of Service via multiple wildcards",
      "x_generator": {
        "engine": "cve-kit 1.0.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
    "assignerShortName": "openjs",
    "cveId": "CVE-2026-4923",
    "datePublished": "2026-03-26T19:02:00.729Z",
    "dateReserved": "2026-03-26T18:05:44.717Z",
    "dateUpdated": "2026-03-27T13:58:03.925Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-4923",
      "date": "2026-05-21",
      "epss": "0.00057",
      "percentile": "0.17789"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-4923\",\"sourceIdentifier\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"published\":\"2026-03-26T19:17:08.187\",\"lastModified\":\"2026-04-16T18:03:37.620\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"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\\nUnsafe examples:\\n\\n/*foo-*bar-:baz\\n/*a-:b-*c-:d\\n/x/*a-:b/*c/y\\n\\nSafe examples:\\n\\n/*foo-:bar\\n/*foo-:bar-*baz\\n\\nPatches:\\n\\nUpgrade to version 8.4.0.\\n\\nWorkarounds:\\n\\nIf you are using multiple wildcard parameters, you can check the regex output with a tool such as https://makenowjust-labs.github.io/recheck/playground/ to confirm whether a path is vulnerable.\"},{\"lang\":\"es\",\"value\":\"Impacto:\\n\\nAl usar m\u00faltiples comodines, combinados con al menos un par\u00e1metro, se puede generar una expresi\u00f3n regular que es vulnerable a ReDoS. Esta vulnerabilidad de retroceso requiere que el segundo comod\u00edn est\u00e9 en un lugar distinto al final de la ruta.\\n\\nEjemplos no seguros:\\n\\n/*foo-*bar-:baz\\n/*a-:b-*c-:d\\n/x/*a-:b/*c/y\\n\\nEjemplos seguros:\\n\\n/*foo-:bar\\n/*foo-:bar-*baz\\n\\nParches:\\n\\nActualice a la versi\u00f3n 8.4.0.\\n\\nSoluciones alternativas:\\n\\nSi est\u00e1 utilizando m\u00faltiples par\u00e1metros comod\u00edn, puede verificar la salida de la expresi\u00f3n regular con una herramienta como https://makenowjust-labs.github.io/recheck/playground/ para confirmar si una ruta es vulnerable.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":5.9,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.2,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-1333\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:pillarjs:path-to-regexp:*:*:*:*:*:node.js:*:*\",\"versionStartIncluding\":\"8.0.0\",\"versionEndExcluding\":\"8.4.0\",\"matchCriteriaId\":\"DB421812-F7E3-4CC5-B02B-53CCBFDFB671\"}]}]}],\"references\":[{\"url\":\"https://cna.openjsf.org/security-advisories.html\",\"source\":\"ce714d77-add3-4f53-aff5-83d477b104bb\",\"tags\":[\"Third Party Advisory\"]}]}}",
    "vulnrichment": {
      "containers": "{\"cna\": {\"title\": \"path-to-regexp vulnerable to Regular Expression Denial of Service via multiple wildcards\", \"credits\": [{\"lang\": \"en\", \"type\": \"remediation developer\", \"value\": \"blakeembrey\"}, {\"lang\": \"en\", \"type\": \"remediation reviewer\", \"value\": \"UlisesGascon\"}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"version\": \"3.1\", \"baseScore\": 5.9, \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"vendor\": \"path-to-regexp\", \"product\": \"path-to-regexp\", \"versions\": [{\"status\": \"affected\", \"version\": \"8.0.0\", \"lessThan\": \"8.4.0\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"8.4.0\", \"versionType\": \"semver\"}], \"packageURL\": \"pkg:npm/path-to-regexp\", \"defaultStatus\": \"unaffected\"}], \"references\": [{\"url\": \"https://cna.openjsf.org/security-advisories.html\"}], \"x_generator\": {\"engine\": \"cve-kit 1.0.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"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\\nUnsafe examples:\\n\\n/*foo-*bar-:baz\\n/*a-:b-*c-:d\\n/x/*a-:b/*c/y\\n\\nSafe examples:\\n\\n/*foo-:bar\\n/*foo-:bar-*baz\\n\\nPatches:\\n\\nUpgrade to version 8.4.0.\\n\\nWorkarounds:\\n\\nIf you are using multiple wildcard parameters, you can check the regex output with a tool such as https://makenowjust-labs.github.io/recheck/playground/ to confirm whether a path is vulnerable.\", \"supportingMedia\": [{\"type\": \"text/html\", \"value\": \"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\\nUnsafe examples:\\n\\n/*foo-*bar-:baz\\n/*a-:b-*c-:d\\n/x/*a-:b/*c/y\\n\\nSafe examples:\\n\\n/*foo-:bar\\n/*foo-:bar-*baz\\n\\nPatches:\\n\\nUpgrade to version 8.4.0.\\n\\nWorkarounds:\\n\\nIf you are using multiple wildcard parameters, you can check the regex output with a tool such as https://makenowjust-labs.github.io/recheck/playground/ to confirm whether a path is vulnerable.\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-1333\", \"description\": \"CWE-1333: Inefficient Regular Expression Complexity\"}]}], \"providerMetadata\": {\"orgId\": \"ce714d77-add3-4f53-aff5-83d477b104bb\", \"shortName\": \"openjs\", \"dateUpdated\": \"2026-03-26T19:02:00.729Z\"}}, \"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-4923\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-03-27T13:46:47.360477Z\"}}}], \"providerMetadata\": {\"shortName\": \"CISA-ADP\", \"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"dateUpdated\": \"2026-03-27T13:46:51.745Z\"}}]}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-4923\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-03-26T19:02:00.729Z\", \"dateReserved\": \"2026-03-26T18:05:44.717Z\", \"assignerOrgId\": \"ce714d77-add3-4f53-aff5-83d477b104bb\", \"datePublished\": \"2026-03-26T19:02:00.729Z\", \"assignerShortName\": \"openjs\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

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.