Vulnerability in Yubico Libfido2

CVE-2026-40947

Yubico libfido2 before 1.17.0, python-fido2 before 2.2.0, and yubikey-manager before 5.9.1 have an unintended DLL search path.

EPSS: 0.000 (0.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 2.9 (Low). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N.

Affected products

Yubico Libfido2 — versions 0
Yubico Python-fido2 — versions 0
Yubico Yubikey-manager — versions 0

Weakness classification (CWE)

CWE-426 — Untrusted Search Path

References

www.yubico.com/support/security-advisories/ysa-2026-01/

Frequently asked questions

What is CVE-2026-40947?: CVE-2026-40947 is a low-severity vulnerability in Yubico Libfido2, classified under Untrusted Search Path. CVSS score: 2.9/10. Published 2026-04-15.
How severe is CVE-2026-40947?: Low severity. CVSS v3 base score is 2.9 out of 10.