Interpretation Conflict in fast-uri - CVE-2026-75931
Published: August 25, 2026
Vulnerability identifier: #VU145069
CSH Severity: Medium
CVSS v4: 8.7 [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]
CVE-ID: CVE-2026-75931
CWE-ID: CWE-436
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass host-based policy checks.
The vulnerability exists due to interpretation conflict in the resolve() host canonicalization logic when resolving scheme-relative references against a scheme-bearing base. A remote attacker can supply a specially crafted scheme-relative reference to bypass host-based policy checks.
Re-parsing the resolved URI can yield a different host than the one returned by resolve().
Affected software
fast-uri
How to mitigate CVE-2026-75931
Install security update from vendor's website.
fast-uri - addressed in versions 2.4.5, 3.1.6, 4.1.3