What’s Vulnerable › Vulnerabilities

CVE-2021-27217

• Severity: medium (CVSS 4.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-03-04 · updated 2026-06-17
• Weakness: CWE-125

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.

Affected products

• Yubico Yubihsm-Shell: through 2.0.3

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
• https://www.yubico.com/support/security-advisories/ysa-2021-01/

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