What is CVE-2026-16221?

CVE-2026-16221 is a high-severity vulnerability in Fast-uri, classified under CWE-436. CVSS score: 7.5/10. Published 2026-07-19.

How severe is CVE-2026-16221?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Fast-uri

CVE-2026-16221

Impact: fast-uri versions from 2.3.1 through 4.1.0 (including the 3.x line up to 3.1.3 and the 2.x line up to 2.4.2) do not treat a literal backslash character (U+005C) as an authority delimiter. Node's native WHATWG URL parser, used by fe…

EPSS: 0.002 (12.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

Affected products

Fast-uri — versions 2.3.1, 2.4.3, 3.0.0

Weakness classification (CWE)

CWE-436

References

ce714d77-add3-4f53-aff5-83d477b104bb
ce714d77-add3-4f53-aff5-83d477b104bb

Frequently asked questions

What is CVE-2026-16221?: CVE-2026-16221 is a high-severity vulnerability in Fast-uri, classified under CWE-436. CVSS score: 7.5/10. Published 2026-07-19.
How severe is CVE-2026-16221?: High severity. CVSS v3 base score is 7.5 out of 10.