CVE-2026-18446

Source
https://cve.org/CVERecord?id=CVE-2026-18446
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-18446.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-18446
Aliases
  • GHSA-7p8r-x3mc-p8w7
Downstream
Published
2026-07-31T14:37:01.584Z
Modified
2026-08-02T03:31:45.734801933Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N CVSS Calculator
Summary
fast-uri vulnerable to host confusion via backslash authority introducer
Details

fast-uri before 4.1.2, 3.1.5, and 2.4.4 requires a literal double forward slash to recognize a URI authority, so a reference that uses a backslash based introducer in place of it (backslash backslash, forward slash backslash, or backslash forward slash) is parsed with no authority and folds into the path. Node's native WHATWG URL parser instead treats a backslash as interchangeable with a forward slash for special schemes, so the two parsers extract different hosts from the same input. Applications that use fast-uri to enforce host based policy such as allowlists, SSRF filtering, or redirect validation before passing the same URL into Node's URL or fetch consumers can be steered to an unintended host. Upgrade to fast-uri 4.1.2, 3.1.5, or 2.4.4.

Database specific
{
    "cwe_ids": [
        "CWE-436"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18446.json",
    "cna_assigner": "openjs"
}
References

Affected packages

Git / github.com/fastify/fast-uri

Affected ranges

Type
GIT
Repo
https://github.com/fastify/fast-uri
Events
Database specific
{
    "source": "AFFECTED_FIELD",
    "extracted_events": [
        {
            "introduced": "4.0.0"
        },
        {
            "fixed": "4.1.2"
        },
        {
            "introduced": "3.0.0"
        },
        {
            "fixed": "3.1.5"
        },
        {
            "introduced": "0"
        },
        {
            "fixed": "2.4.4"
        }
    ]
}

Affected versions

v0.*
v0.0.1
v0.0.2
v1.*
v1.0.0
v1.0.1
v2.*
v2.0.0
v2.1.0
v2.2.0
v2.3.0
v2.3.1
v2.4.0
v2.4.1
v2.4.2
v2.4.3
v3.*
v3.0.0
v3.0.1
v3.0.2
v3.0.3
v3.0.4
v3.0.5
v3.0.6
v3.1.0
v3.1.1
v3.1.2
v3.1.3
v3.1.4
v4.*
v4.0.0
v4.0.1
v4.1.0
v4.1.1

Database specific

source
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-18446.json"