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fast-uri vulnerable to host confusion via unchecked WHATWG host canonicalization

Type: advisorySource: Official CVE List1 source record

fast-uri is a dependency-free RFC 3986 URI parser and serializer for Node.js. In versions from 2.4.2 through 2.4.7, from 3.1.3 through 3.1.8, and from 4.0.1 through 4.2.2, for HTTP-family schemes the canonicalizeHost() function passes the parsed host to the WHATWG URL parser and adopts its hostname without checking that the parser consumed the entire input as a host, so the authority can be silently rewritten: data before an at-sign is dropped and tab, carriage-return, and line-feed characters are stripped, with no error reported. An application that enforces host-based policy such as denylists, loopback filtering, redirect validation, or outbound proxy routing on one representation can then see the canonical host diverge from what it checked, allowing traffic to be steered to an unintended destination. The issue is fixed in fast-uri 2.4.8, 3.1.9, and 4.2.3, and users should upgrade to one of these versions or later. As a workaround, reject an authority that contains more than one at-sign or any tab, carriage-return, or line-feed before calling fast-uri, or treat any non-empty parse error as fatal and compare hosts only from the same parse result.

Announced Source revision 1
Original source ↗

CVE-2026-110180

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-110180

fast-uri

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "vendor": "fast-uri",
    "product": "fast-uri",
    "versions": [
      {
        "status": "affected",
        "version": "2.4.2",
        "lessThan": "2.4.8",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "2.4.8",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "3.1.3",
        "lessThan": "3.1.9",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "3.1.9",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "4.0.1",
        "lessThan": "4.2.3",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "4.2.3",
        "versionType": "semver"
      }
    ],
    "packageURL": "pkg:npm/fast-uri",
    "defaultStatus": "unaffected"
  }
]
Related CVEs
CVE-2026-110180

Source reference: /cveMetadata/cveId

Publisher severity

medium

Source reference: /containers/cna/metrics

Event
#42316 · Revision 1
Added to Heist Feed
Publisher date
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