CVE-2021-27217

4.4 mediumEPSS 1.6%

Medium (4.4) in yubico yubihsm-shell. EPSS 1.6% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

4.4 medium

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H

EPSS: 1.6% chance of exploitation in the next 30 days; higher than 75% of CVEs (scores of 2026-10-31)
CWE: CWE-125
Published: 2021-03-04
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

yubico:yubihsm-shell

References

https://blog.inhq.net/posts/yubico-libyubihsm-vuln2
https://github.com/Yubico/yubihsm-shell/releases
https://www.yubico.com/support/security-advisories/ysa-2021-01/
https://blog.inhq.net/posts/yubico-libyubihsm-vuln2
https://github.com/Yubico/yubihsm-shell/releases

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