CVE-2026-13676
HIGHCVSS v3.1: 7.5
Source data as of:
At a glance
- Severity
- HIGH
- CVSS
- 7.5 v3.1 · NVD
- EPSS
- EPSS not provided by FIRST.org for this CVE
- CISA KEV
- No
- Attack conditions (CVSS vector)
- NetworkNo privilegesNo user interaction · Source: NVD Vector
- Published
- 2026-06-29 · Modified: 2026-06-30
- References
- Jump to references (5)
CVSS / EPSS / KEV
Source — CVSS: NVD · EPSS: FIRST.org · KEV: CISA. Data & Sources
Description
fast-uri versions 2.3.1 through 3.1.2 and 4.0.0 fail to canonicalize Unicode (IDN) hostnames for HTTP-family URLs. The IDN conversion path calls a helper that does not exist on the global URL constructor, silently leaving the host in its original Unicode form while normalize() and equal() still return values that differ from a WHATWG-compatible URL parser. Applications that use fast-uri to enforce host-based policy (denylists, loopback filtering, redirect validation, outbound proxy routing) before passing the same URL to Node's URL or fetch can be bypassed when the two implementations resolve the same input to different hosts. Patches: upgrade to fast-uri 3.1.3 for the 3.x line or 4.0.1 for the 4.x line. Workarounds: enforce host policy using the same URL parser used for the actual request, or reject non-ASCII hosts before policy checks.
References
Reference URLs as listed by NVD, grouped by a mechanical match on the link's host/pattern. Labels describe the link type only.
- Vendor advisory https://cna.openjsf.org/security-advisories.html
- Vendor advisory https://github.com/fastify/fast-uri/security/advisories/GHSA-4c8g-83qw-93j6
- Distro https://access.redhat.com/security/cve/CVE-2026-13676
- Distro https://bugzilla.redhat.com/show_bug.cgi?id=2494197
- Distro https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-13676.json