Interpretation Conflict in fast-uri - CVE-2026-18446
Published: August 1, 2026
Vulnerability identifier: #VU140701
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-18446
CWE-ID: CWE-436
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Affected software:
fast-uri
fast-uri
Detailed vulnerability description
The vulnerability allows a remote attacker to bypass host-based policy checks and steer requests to an unintended destination.
The vulnerability exists due to interpretation conflict in the fast-uri URI parser when parsing references that use backslash-based authority introducers. A remote attacker can supply a specially crafted URL to bypass host-based policy checks and steer requests to an unintended destination.
The issue arises from inconsistent host extraction between fast-uri and Node's WHATWG URL handling for special schemes.
How to mitigate CVE-2026-18446
Install security update from vendor's website.