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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-32489
• https://blog.inhq.net/posts/yubico-libyubihsm-vuln2/#second-attack-variant-cve-pending