CVE-2021-43399
The Yubico YubiHSM YubiHSM2 library 2021.08, included in the yubihsm-shell project, does not...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2021-43399- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 7.8 High
AV:N/AC:L/Au:N/C:N/I:N/A:C - Weakness
- CWE-787
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2021-43399- Updated
- 2026-11-02
EUVDEUVD-2021-30334 No score
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.
- Record
EUVD-2021-30334- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-vrp3-rwcp-4q77
The Yubico YubiHSM YubiHSM2 library 2021.08, included in the yubihsm-shell project, does not...
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.
- Record
GHSA-vrp3-rwcp-4q77- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-787
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-43399 is a high vulnerability (CVSS 7.5) in Yubico Yubihsm 2 Software Development Kit, published December 8, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.41%, the 72nd percentile. No source names a fixed version.