GHSA-V39H-62P7-JPJC

Vulnerability from github – Published: 2026-05-08 19:13 – Updated: 2026-05-08 19:13
VLAI
Summary
fast-uri vulnerable to host confusion via percent-encoded authority delimiters
Details

Impact

fast-uri v3.1.1 and earlier decodes percent-encoded authority delimiters (%40 as @, %3A as :) inside the host component and serializes them back as raw characters. This changes the URI structure, turning a hostname into userinfo plus a different host.

For example, http://trusted.com%40evil.com/ normalizes to http://trusted.com@evil.com/, which reparses as host evil.com with userinfo trusted.com.

Applications that normalize untrusted URLs before host allowlist checks, redirect validation, or outbound request routing can be steered to a different authority than the original URL appeared to contain.

Patches

Upgrade to fast-uri >= 3.1.2.

Workarounds

None. Upgrade to the patched version.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.1.1"
      },
      "package": {
        "ecosystem": "npm",
        "name": "fast-uri"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-6322"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-436"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-08T19:13:01Z",
    "nvd_published_at": "2026-05-05T11:16:33Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\n`fast-uri` v3.1.1 and earlier decodes percent-encoded authority delimiters (`%40` as `@`, `%3A` as `:`) inside the host component and serializes them back as raw characters. This changes the URI structure, turning a hostname into userinfo plus a different host.\n\nFor example, `http://trusted.com%40evil.com/` normalizes to `http://trusted.com@evil.com/`, which reparses as host `evil.com` with userinfo `trusted.com`.\n\nApplications that normalize untrusted URLs before host allowlist checks, redirect validation, or outbound request routing can be steered to a different authority than the original URL appeared to contain.\n\n### Patches\n\nUpgrade to `fast-uri` \u003e= 3.1.2.\n\n### Workarounds\n\nNone. Upgrade to the patched version.",
  "id": "GHSA-v39h-62p7-jpjc",
  "modified": "2026-05-08T19:13:01Z",
  "published": "2026-05-08T19:13:01Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/fastify/fast-uri/security/advisories/GHSA-v39h-62p7-jpjc"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6322"
    },
    {
      "type": "WEB",
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/fastify/fast-uri"
    }
  ],
  "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 percent-encoded authority delimiters"
}


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.