CVE-2021-43399

Public Exploit

Description

The Yubico YubiHSM YubiHSM2 library 2021.08, included in the yubihsm-shell project, does not properly validate the length of some operations including SSH signing requests, and some data operations received from a YubiHSM 2 device.

Category

7.5
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.37%
Vendor Advisory yubico.com
Affected: n/a n/a
Published at:
Updated at:

References

Link Tags
https://www.yubico.com/support/security-advisories/ysa-2021-04/ vendor advisory
https://blog.inhq.net/posts/yubico-yubihsm-shell-vuln3/ third party advisory exploit

Frequently Asked Questions

What is the severity of CVE-2021-43399?
CVE-2021-43399 has been scored as a high severity vulnerability.
How to fix CVE-2021-43399?
To fix CVE-2021-43399, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-43399 being actively exploited in the wild?
It is possible that CVE-2021-43399 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.