CVE-2018-20340

Name: CVE-2018-20340
Creator: NVD / NIST
Published: 2019-03-21T16:00:35.983+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 0.50%

Last modified Jun 17, 2026

CVE-2018-20340 is a vulnerability of currently unknown severity. Yubico libu2f-host 1.1.6 contains unchecked buffers in devs.c, which could enable a malicious token to exploit a buffer overflow. An attacker could use this to attempt to execute malicious code using a crafted USB device masquerading as a security token on a computer where the affected library is currently in use. EPSS estimates a 0.50% chance of exploitation in the next 30 days.

Description

Yubico libu2f-host 1.1.6 contains unchecked buffers in devs.c, which could enable a malicious token to exploit a buffer overflow. An attacker could use this to attempt to execute malicious code using a crafted USB device masquerading as a security token on a computer where the affected library is currently in use. It is not possible to perform this attack with a genuine YubiKey.

Metrics

EPSS Probability

0.50%

38.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-119

Affected Software

Vendor	Product	Versions
Yubico	Libu2f-Host	1.1.6
Debian	Debian Linux	9.0

References

https://blog.inhq.net/posts/yubico-libu2f-host-vuln-part1/
https://developers.yubico.com/libu2f-host/Release_Notes.htmlRelease Notes, Vendor Advisory
https://seclists.org/bugtraq/2019/Feb/23Mailing List, Third Party Advisory
https://security.gentoo.org/glsa/202004-15
https://www.debian.org/security/2019/dsa-4389Third Party Advisory
https://www.yubico.com/support/security-advisories/ysa-2019-01/Patch, Vendor Advisory
https://blog.inhq.net/posts/yubico-libu2f-host-vuln-part1/
https://developers.yubico.com/libu2f-host/Release_Notes.htmlRelease Notes, Vendor Advisory
https://seclists.org/bugtraq/2019/Feb/23Mailing List, Third Party Advisory
https://security.gentoo.org/glsa/202004-15
https://www.debian.org/security/2019/dsa-4389Third Party Advisory
https://www.yubico.com/support/security-advisories/ysa-2019-01/Patch, Vendor Advisory

Timeline

Published: Mar 21, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2018-20340?

How severe is CVE-2018-20340?

Severity scoring for CVE-2018-20340 is pending analysis. The EPSS model estimates a 0.50% probability of exploitation in the next 30 days.

How do I fix CVE-2018-20340?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2018-20340?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST