Vulnerability-Lookup

GHSA-QW65-CVWX-89V3

Vulnerability from github – Published: 2026-09-28 21:24 – Updated: 2026-09-28 21:24

Summary

fast-uri vulnerable to authority injection via an unvalidated port in serialize

Details

Impact

fast-uri serializes the port component of a URI without validating it. When recomposing the authority, fast-uri escapes the userinfo and host components but concatenates the port verbatim, so a port value that is not a sequence of digits can inject authority delimiters. For example, serializing a component whose port is @127.0.0.1:8124 produces http://trusted.example:@127.0.0.1:8124/app, demoting the intended host to userinfo and pointing the authority at an attacker-controlled host. Both fast-uri and Node's URL read the result back as the attacker's host with no error, so re-validating the built URI does not catch it.

This affects applications that build URIs from parts and assign untrusted data to the port component (for example a fixed host from configuration and a port taken from user input or a service record). The same path is reachable through serialize(), normalize(), and equal() in their object forms. A port obtained from parse() is always digits and is not affected.

Patches

This vulnerability has been patched in fast-uri 4.1.4, 3.1.7, and 2.4.6. recomposeAuthority now rejects any port that is not *DIGIT per RFC 3986. All users should upgrade.

Workarounds

If upgrading is not immediately possible, validate the port value against the RFC 3986 grammar (digits only) before passing a component to serialize(), normalize(), or equal(), and reject anything else, for example if (!/^\d*$/.test(String(port))) throw new Error('invalid port').

Severity

7.5 (High)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "fast-uri"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.4.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "fast-uri"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
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            }
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        }
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        "ecosystem": "npm",
        "name": "fast-uri"
      },
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          "events": [
            {
              "introduced": "4.0.0"
            },
            {
              "fixed": "4.1.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-84292"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-116"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-28T21:24:39Z",
    "nvd_published_at": "2026-09-02T20:17:39Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\n`fast-uri` serializes the `port` component of a URI without validating it. When recomposing the authority, `fast-uri` escapes the userinfo and host components but concatenates the port verbatim, so a `port` value that is not a sequence of digits can inject authority delimiters. For example, serializing a component whose `port` is `@127.0.0.1:8124` produces `http://trusted.example:@127.0.0.1:8124/app`, demoting the intended host to userinfo and pointing the authority at an attacker-controlled host. Both `fast-uri` and Node\u0027s `URL` read the result back as the attacker\u0027s host with no error, so re-validating the built URI does not catch it.\n\nThis affects applications that build URIs from parts and assign untrusted data to the `port` component (for example a fixed host from configuration and a port taken from user input or a service record). The same path is reachable through `serialize()`, `normalize()`, and `equal()` in their object forms. A `port` obtained from `parse()` is always digits and is not affected.\n\n### Patches\n\nThis vulnerability has been patched in fast-uri `4.1.4`, `3.1.7`, and `2.4.6`. `recomposeAuthority` now rejects any port that is not `*DIGIT` per RFC 3986. All users should upgrade.\n\n### Workarounds\n\nIf upgrading is not immediately possible, validate the `port` value against the RFC 3986 grammar (digits only) before passing a component to `serialize()`, `normalize()`, or `equal()`, and reject anything else, for example `if (!/^\\d*$/.test(String(port))) throw new Error(\u0027invalid port\u0027)`.",
  "id": "GHSA-qw65-cvwx-89v3",
  "modified": "2026-09-28T21:24:39Z",
  "published": "2026-09-28T21:24:39Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/fastify/fast-uri/security/advisories/GHSA-qw65-cvwx-89v3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-84292"
    },
    {
      "type": "WEB",
      "url": "https://github.com/fastify/fast-uri/commit/820e8478dd7da3d09f187bfaf35d50b71f67b8b4"
    },
    {
      "type": "WEB",
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/fastify/fast-uri"
    },
    {
      "type": "WEB",
      "url": "https://github.com/fastify/fast-uri/releases/tag/v2.4.6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/fastify/fast-uri/releases/tag/v3.1.7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/fastify/fast-uri/releases/tag/v4.1.4"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "fast-uri vulnerable to authority injection via an unvalidated port in serialize"
}

CVE-2026-84292 (GCVE-0-2026-84292)

Vulnerability from cvelistv5 – Published: 2026-09-02 20:09 – Updated: 2026-09-03 13:16

Title

fast-uri vulnerable to authority injection via an unvalidated port in serialize

Summary

fast-uri serializes the port component of a URI without validating it. When recomposing the authority, the userinfo and host components are escaped but the port is concatenated verbatim, so a port value that is not a sequence of digits can inject authority delimiters, demoting the intended host to userinfo and pointing the authority at an attacker-controlled host. Both fast-uri and Node's URL read the result back as the attacker's host with no error, so re-validating the built URI does not catch it. This affects applications that build URIs from parts and assign untrusted data to the port component through the serialize, normalize, or equal functions in their object forms. The issue affects fast-uri versions before 2.4.6, from 3.0.0 before 3.1.7, and from 4.0.0 before 4.1.4. It is fixed in 2.4.6, 3.1.7, and 4.1.4, where recomposeAuthority rejects any port that is not a digit sequence per RFC 3986.

Severity

7.5 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-03 13:16 UTC

CWE

CWE-116 - Improper Encoding or Escaping of Output

Assigner

openjs redhat root

References

2 references

URL	Tags
https://github.com/fastify/fast-uri/security/advi…
https://cna.openjsf.org/security-advisories.html

Impacted products

1 product

Vendor	Product	Version
fast-uri	fast-uri	Affected: 0 , < 2.4.6 (semver) Unaffected: 2.4.6 (semver) Affected: 3.0.0 , < 3.1.7 (semver) Unaffected: 3.1.7 (semver) Affected: 4.0.0 , < 4.1.4 (semver) Unaffected: 4.1.4 (semver)

Credits

YashvantHange mcollina UlisesGascon

Show details on NVD website

JSON

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Sightings

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Nomenclature

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Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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