CVE-2021-27217

Name: CVE-2021-27217
Creator: NVD / NIST
Published: 2021-03-04T18:15:14.05+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.4/10EPSS 1.59%

Last modified Jun 17, 2026

CVE-2021-27217 is a medium-severity vulnerability rated 4.4/10 on the CVSS scale. 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. EPSS estimates a 1.59% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

4.4/10

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

EPSS Probability

1.59%

72.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-125

Affected Software

Vendor	Product	Versions
Yubico	Yubihsm-Shell	<= 2.0.3

References

https://blog.inhq.net/posts/yubico-libyubihsm-vuln2Exploit, Third Party Advisory
https://github.com/Yubico/yubihsm-shell/releasesRelease Notes, Third Party Advisory
https://www.yubico.com/support/security-advisories/ysa-2021-01/Vendor Advisory
https://blog.inhq.net/posts/yubico-libyubihsm-vuln2Exploit, Third Party Advisory
https://github.com/Yubico/yubihsm-shell/releasesRelease Notes, Third Party Advisory
https://www.yubico.com/support/security-advisories/ysa-2021-01/Vendor Advisory

Timeline

Published: Mar 4, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-27217?

How severe is CVE-2021-27217?

CVE-2021-27217 has a CVSS score of 4.4/10 (MEDIUM severity). The EPSS model estimates a 1.59% probability of exploitation in the next 30 days.

How do I fix CVE-2021-27217?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-27217?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST