TI-2021-19344 Aliases CVE-2021-43399 GHSA-vrp3-rwcp-4q77

The Yubico YubiHSM YubiHSM2 library 2021.08, included in the yubihsm-shell project, does…

LOW 36CWE-787Published 2021-12-08 · Updated 2024-08-04

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-787 and the CVSS impact.

Summary

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.

Why it matters now

EPSS 0.01413 72nd percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
—	—	all versions	—	No fix listed	CNA

— Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:yubico:yubihsm_2_software_development_kit::::::::	up to 2021.08	Vulnerable	Yubico

cpe:2.3:a:yubico:yubihsm_2_software_development_kit:*:*:*:*:*:*:*:* Versions up to 2021.08 Vulnerable ·Yubico

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2021-43399
2026-10-03 Alias added: GHSA-vrp3-rwcp-4q77

References

Exploit 1

https://blog.inhq.net/posts/yubico-yubihsm-shell-vuln3/

Advisory 1

https://www.yubico.com/support/security-advisories/ysa-2021-04/

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences