CVE-2021-27217 json
An issue was discovered in the _send_secure_msg() function of Yubico yubihsm-shell through 2.0.3.
published 2021-03-04 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-13982
- cvss
- 4.4
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.6%
- EPSS 1.6% chance of exploitation in 30 days, percentile 75%
- public exploits
- 0
- none known
Summary
An issue was discovered in the _send_secure_msg() function of Yubico yubihsm-shell through 2.0.3. The function does not correctly validate the embedded length field of an authenticated message received from the device. Out-of-bounds reads performed by aes_remove_padding() can crash the running process, depending on the memory layout. This could be used by an attacker to cause a client-side denial of service. The yubihsm-shell project is included in the YubiHSM 2 SDK product.
Exploit prediction
1.59% chance of exploitation in the next 30 days, higher than 75% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- blog.inhq.net https://blog.inhq.net/posts/yubico-libyubihsm-vuln2 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 4.4 | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H |
| NVD | 2.0 | 3.5 | AV:N/AC:M/Au:S/C:N/I:N/A:P |
Classification
- Weakness
-
- CWE-125 Out-of-bounds Read
References
-
blog.inhq.net
/posts/yubico-libyubihsm-vuln2
exploit, third-party-advisory
-
yubico.com
/support/security-advisories/ysa-2021-01/
vendor-advisory
-
github.com
/Yubico/yubihsm-shell/releases
release-notes, third-party-advisory
Sources
- CVE List CVE-2021-27217
- NVD CVE-2021-27217
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