ghsa-4c8g-83qw-93j6

CVSS 7.5 github

Description

### Impact `fast-uri` versions `>= 2.3.1, <= 4.0.0` fail to canonicalize Unicode/IDN hostnames for HTTP-family URLs. The IDN conversion path calls `URL.domainToASCII(...)` on the global WHATWG `URL` constructor, where that helper does not exist. The resulting `TypeError` is silently routed into `parsed.error`, but `parse()`, `normalize()`, and `equal()` all return with the host left in its original Unicode form. For example, `http://127。0。0。1/` is treated by `fast-uri` as host `127。0。0。1`, while Node's WHATWG URL parser and `fetch()` canonicalize the same input to `127.0.0.1`. Applications that use `fast-uri` to enforce host-based policy (denylists, loopback filtering, redirect validation, outbound proxy routing) before passing the same URL into Node's URL or `fetch()` consumers see a policy/use desync and can be steered to an unintended destination. ### Patches Upgrade to `fast-uri` v4.0.1, v3.1.3, or v2.4.2 ### Workarounds None. Upgrade to the patched version.

Timeline

Published: unknown
Last Modified: unknown

CVSS Details

CVSS details not available.

Affected Products

No product information available.

Weaknesses (CWE)

CWE-436 CWE-551

References

Linked Vulnerabilities

No linked vulnerabilities found.

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "fast-uri"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.0.0"
            },
            {
              "fixed": "4.0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "fast-uri"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.1.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "fast-uri"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.3.1"
            },
            {
              "fixed": "2.4.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-13676"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-436",
      "CWE-551"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-21T19:03:11Z",
    "nvd_published_at": "2026-06-29T14:16:47Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\n`fast-uri` versions `>= 2.3.1, <= 4.0.0` fail to canonicalize Unicode/IDN hostnames for HTTP-family URLs. The IDN conversion path calls `URL.domainToASCII(...)` on the global WHATWG `URL` constructor, where that helper does not exist. The resulting `TypeError` is silently routed into `parsed.error`, but `parse()`, `normalize()`, and `equal()` all return with the host left in its original Unicode form.\n\nFor example, `http://127。0。0。1/` is treated by `fast-uri` as host `127。0。0。1`, while Node's WHATWG URL parser and `fetch()` canonicalize the same input to `127.0.0.1`.\n\nApplications that use `fast-uri` to enforce host-based policy (denylists, loopback filtering, redirect validation, outbound proxy routing) before passing the same URL into Node's URL or `fetch()` consumers see a policy/use desync and can be steered to an unintended destination.\n\n### Patches\n\nUpgrade to `fast-uri` v4.0.1, v3.1.3, or v2.4.2\n\n### Workarounds\n\nNone. Upgrade to the patched version.",
  "id": "GHSA-4c8g-83qw-93j6",
  "modified": "2026-09-11T15:32:25Z",
  "published": "2026-07-21T19:03:11Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/fastify/fast-uri/security/advisories/GHSA-4c8g-83qw-93j6"
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      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-13676"
    },
    {
      "type": "WEB",
      "url": "https://github.com/fastify/fast-uri/pull/188"
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    {
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      "url": "https://github.com/fastify/fast-uri/commit/2a6d357a18a68e6d812824379fd3388a1ae50d05"
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      "url": "https://github.com/fastify/fast-uri/commit/21ea1f9d70495c931f55dff893a8fa38f4f2e6bd"
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      "type": "WEB",
      "url": "https://github.com/fastify/fast-uri/commit/01db48010f594b98f7b323be18b393791c66ed1d"
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    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:63371"
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    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:61314"
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      "url": "https://access.redhat.com/errata/RHSA-2026:57194"
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      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-13676"
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    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2494197"
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    {
      "type": "WEB",
      "url": "https://cna.openjsf.org/security-advisories.html"
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    {
      "type": "PACKAGE",
      "url": "https://github.com/fastify/fast-uri"
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      "type": "WEB",
      "url": "https://github.com/fastify/fast-uri/releases/tag/v2.4.2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/fastify/fast-uri/releases/tag/v3.1.3"
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    {
      "type": "WEB",
      "url": "https://github.com/fastify/fast-uri/releases/tag/v4.0.1"
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    {
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      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-13676.json"
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    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:37186"
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      "url": "https://access.redhat.com/errata/RHSA-2026:50758"
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    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:51196"
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    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:51197"
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    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:51342"
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    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:51348"
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    {
      "type": "WEB",
      "url": "https://access.redhat.com/errata/RHSA-2026:51349"
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    {
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      "url": "https://access.redhat.com/errata/RHSA-2026:54760"
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  ],
  "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 host confusion via failed IDN canonicalization"
}

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