CVE-2026-13676
fast-uri vulnerable to host confusion via failed IDN canonicalization
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.
INFO
Published Date :
June 29, 2026, 1:22 p.m.
Last Modified :
June 29, 2026, 1:22 p.m.
Remotely Exploit :
No
Source :
openjs
Affected Products
The following products are affected by CVE-2026-13676
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | ce714d77-add3-4f53-aff5-83d477b104bb |
Solution
- Upgrade fast-uri to 3.1.3 or 4.0.1.
- Use consistent URL parsing for policy enforcement.
- Reject non-ASCII hosts before policy checks.
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CVE-2026-13676 vulnerability anywhere in the article.