FKIE_CVE-2026-84394

Vulnerability from fkie_nvd - Published: 2026-09-03 05:16 - Updated: 2026-09-04 16:12
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Summary
fast-uri accepts a host that contains an unbalanced or misplaced authority bracket without reporting an error. A host that starts with an opening bracket but does not end with a closing bracket is neither validated as an IP literal nor canonicalized as a domain name, so parse() returns it as the host with error undefined, while Node's URL and the HTTP clients built on it resolve the same string to a different host. An application that reads the parsed host to make a host decision, such as an SSRF denylist, a redirect allowlist, or proxy routing, and then passes the original URL to an HTTP client evaluates its policy against a string that is not the host the request reaches. The same host is carried through normalize, equal, and resolve. This affects fast-uri versions 2.4.5, 3.1.6, and 4.1.3, and is fixed in 2.4.6, 3.1.7, and 4.1.4, where parse() reports a malformed host for any host that contains a bracket but is not a valid IPv6 literal.
References
ce714d77-add3-4f53-aff5-83d477b104bbhttps://cna.openjsf.org/security-advisories.htmlVendor Advisory
ce714d77-add3-4f53-aff5-83d477b104bbhttps://github.com/fastify/fast-uri/security/advisories/GHSA-58mr-gqgx-xq4gMitigation, Vendor Advisory
Impacted products
Vendor Product Version
openjsf fast-uri 2.4.5
openjsf fast-uri 3.1.6
openjsf fast-uri 4.1.3
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:npm/fast-uri",
          "product": "fast-uri",
          "vendor": "fast-uri",
          "versions": [
            {
              "lessThan": "2.4.6",
              "status": "affected",
              "version": "2.4.5",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "2.4.6",
              "versionType": "semver"
            },
            {
              "lessThan": "3.1.7",
              "status": "affected",
              "version": "3.1.6",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "3.1.7",
              "versionType": "semver"
            },
            {
              "lessThan": "4.1.4",
              "status": "affected",
              "version": "4.1.3",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "4.1.4",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "ce714d77-add3-4f53-aff5-83d477b104bb"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:openjsf:fast-uri:2.4.5:*:*:*:*:node.js:*:*",
              "matchCriteriaId": "7E247A05-D85A-432A-B9AD-5E109BBBA126",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:openjsf:fast-uri:3.1.6:*:*:*:*:node.js:*:*",
              "matchCriteriaId": "244CB511-E707-46C2-86CA-EB9F166EDF2E",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:openjsf:fast-uri:4.1.3:*:*:*:*:node.js:*:*",
              "matchCriteriaId": "9B9E720F-653C-4B03-BB56-65B68F0253B6",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "fast-uri accepts a host that contains an unbalanced or misplaced authority bracket without reporting an error. A host that starts with an opening bracket but does not end with a closing bracket is neither validated as an IP literal nor canonicalized as a domain name, so parse() returns it as the host with error undefined, while Node\u0027s URL and the HTTP clients built on it resolve the same string to a different host. An application that reads the parsed host to make a host decision, such as an SSRF denylist, a redirect allowlist, or proxy routing, and then passes the original URL to an HTTP client evaluates its policy against a string that is not the host the request reaches. The same host is carried through normalize, equal, and resolve. This affects fast-uri versions 2.4.5, 3.1.6, and 4.1.3, and is fixed in 2.4.6, 3.1.7, and 4.1.4, where parse() reports a malformed host for any host that contains a bracket but is not a valid IPv6 literal."
    }
  ],
  "id": "CVE-2026-84394",
  "lastModified": "2026-09-04T16:12:20.970",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "ce714d77-add3-4f53-aff5-83d477b104bb",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-84394",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-03T13:14:34.742806Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-03T05:16:38.680",
  "references": [
    {
      "source": "ce714d77-add3-4f53-aff5-83d477b104bb",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "source": "ce714d77-add3-4f53-aff5-83d477b104bb",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/fastify/fast-uri/security/advisories/GHSA-58mr-gqgx-xq4g"
    }
  ],
  "sourceIdentifier": "ce714d77-add3-4f53-aff5-83d477b104bb",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-436"
        }
      ],
      "source": "ce714d77-add3-4f53-aff5-83d477b104bb",
      "type": "Secondary"
    }
  ]
}



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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

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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.
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  • 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.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.