Heiko Schäfer discovered a new security issue in the Yubico yubihsm_pkcs11.so driver library, which we disclosed together to Yubico. The YubiHSM PKCS#11 client-side library is designed to interact with Yubico HSM2 hardware security modules. Due to flaws in the memory handling, the library code accidentally returns 8192 bytes of previously used process memory under some circumstances. This impacts the memory confidentiality of the calling program for some usages.