Cyber Resilience

CVE-2021-43399

HighPublic PoC

Published: 08 December 2021

Published
08 December 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0037 59.1th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-43399 is a high-severity Out-of-bounds Write (CWE-787) vulnerability in Yubico Yubihsm 2 Software Development Kit. Its CVSS base score is 7.5 (High).

Operationally, ranked in the top 40.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

yubico
yubihsm 2 software development kit
≤ 2021.08

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-787

Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.

References