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)
{
"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"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
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.
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