CVE-2026-18446

HIGH CVSS 3.1: 7.5 EPSS 0.22%
Updated Sep 02, 2026
Openjsf
Parameter Value
CVSS 7.5 (HIGH)
Affected Versions 3.0.0 — 4.1.2
Fixed In 2.4.4
Type CWE-436
Vendor Openjsf
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
High
Complete data modification
Availability
None
No disruption

CVSS Vector v3.1

Weakness Type (CWE)

Vulnerable Products 3

Configuration From (including) Up to (excluding)
Openjsf Fast-Uri
cpe:2.3:a:openjsf:fast-uri:*:*:*:*:*:node.js:*:*
2.4.4
Openjsf Fast-Uri
cpe:2.3:a:openjsf:fast-uri:*:*:*:*:*:node.js:*:*
3.0.0 3.1.5
Openjsf Fast-Uri
cpe:2.3:a:openjsf:fast-uri:*:*:*:*:*:node.js:*:*
4.0.0 4.1.2