CVE-2026-75931

HIGH CVSS 3.1: 7.5 EPSS 0.23%
Updated Sep 02, 2026
Openjsf
Parameter Value
CVSS 7.5 (HIGH)
Affected Versions 2.4.2 — 4.1.3
Fixed In 2.4.5
Type CWE-436
Vendor Openjsf
Public PoC No

fast-uri is a URI parser for Node.js. It canonicalizes a host to its ASCII form only when the input carries an explicit scheme, so a scheme-relative reference such as a host preceded by two slashes is returned with its host verbatim and no error set. As a result fast-uri's own entry points disagree with each other: parse, resolve, normalize, and equal can yield different hosts for the same input depending only on whether a scheme is written out, and equal can return opposite verdicts for the same pair of hosts.

An application that extracts a host with fast-uri to check it against a policy list and then resolves the same reference can make its decision on one host while the destination is another, enabling host confusion and policy bypass. The affected versions are 2.4.2 up to but not including 2.4.5, 3.1.3 up to but not including 3.1.6, and 4.0.1 up to but not including 4.1.3. The issue is fixed in 2.4.5, 3.1.6, and 4.1.3, which canonicalize the host consistently across the resolve path.

Users should upgrade to a patched version.

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:*:*
2.4.2 2.4.5
Openjsf Fast-Uri
cpe:2.3:a:openjsf:fast-uri:*:*:*:*:*:node.js:*:*
3.1.3 3.1.6
Openjsf Fast-Uri
cpe:2.3:a:openjsf:fast-uri:*:*:*:*:*:node.js:*:*
4.0.1 4.1.3