CVE-2021-32489

low-risk
Published 2021-05-10

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 because response_msg.st.len=8 can be accepted but triggers an integer overflow, which causes CRYPTO_cbc128_decrypt (in OpenSSL) to encounter an undersized buffer and experience a segmentation fault. The yubihsm-shell project is included in the YubiHSM 2 SDK product.

Do I need to act?

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0.99% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
4
CVSS 4.4/10 Medium
NETWORK / HIGH complexity

Affected Products (1)

Yubihsm-Shell

Affected Vendors

Yubico

References (2)

Exploit https://blog.inhq.net/posts/yubico-libyubihsm-vuln2/#second-attack-variant-cve-p...
Exploit https://blog.inhq.net/posts/yubico-libyubihsm-vuln2/#second-attack-variant-cve-p...
22
/ 100
low-risk
Severity 14/34 · Moderate
Exploitability 3/34 · Minimal
Exposure 5/34 · Minimal