CVE-2021-43399 json
The Yubico YubiHSM YubiHSM2 library 2021.08, included in the yubihsm-shell project, does not properly validate the length of some operation…
published 2021-12-08 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-30334
- cvss
- 7.5
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.4%
- EPSS 1.4% chance of exploitation in 30 days, percentile 72%
- public exploits
- 0
- none known
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.
Exploit prediction
1.41% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- blog.inhq.net https://blog.inhq.net/posts/yubico-yubihsm-shell-vuln3/ referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVD | 2.0 | 7.8 | AV:N/AC:L/Au:N/C:N/I:N/A:C |
Classification
- Weakness
-
- CWE-787 Out-of-bounds Write
References
-
blog.inhq.net
/posts/yubico-yubihsm-shell-vuln3/
exploit, third-party-advisory
-
yubico.com
/support/security-advisories/ysa-2021-04/
vendor-advisory
Sources
- CVE List CVE-2021-43399
- NVD CVE-2021-43399
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