How severe is CVE-2026-40947?

CVE-2026-40947 has a CVSS 3.x base score of 2.9, rated low severity. It is exploitable over local access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-40947 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-40947?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-40947 have an EU (EUVD) identifier?

Yes. CVE-2026-40947 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23135.

When was CVE-2026-40947 published?

CVE-2026-40947 was published on 2026-04-16 and last updated on 2026-06-17.

CVE-2026-40947

CVE-2026-40947 is a low-severity vulnerability with a CVSS 3.x base score of 2.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-426.

Key facts

Severity: Low (CVSS 3.x base score 2.9)
EPSS exploit prediction: 0% (3rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-23135
Weakness: CWE-426
Published: 2026-04-16
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-40947?: CVE-2026-40947 has a CVSS 3.x base score of 2.9, rated low severity. It is exploitable over local access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-40947 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-40947?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-40947 have an EU (EUVD) identifier?: Yes. CVE-2026-40947 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23135.
When was CVE-2026-40947 published?: CVE-2026-40947 was published on 2026-04-16 and last updated on 2026-06-17.

References

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

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