OP-TEE is a Trusted Execution Environment (TEE) designed as companion to a non-secure Linux kernel running on Arm; Cortex-A cores using the TrustZone technology. Starting in version 4.5.0 and prior to version 4.11.0, the RSA PKCS#1 v1.5 decryption implementation in the Hisilicon HPRE crypto driver uses non-constant-time memcmp() for label hash verification and has multiple distinguishable error paths. This creates a Bleichenbacher-style padding oracle that allows an attacker to recover RSA PKCS#1 v1.5 plaintext. Version 4.11.0 contains a patch. As a workaround, disable Hisilicon HPRE RSA driver with CFG_HISILICON_ACC_V3=n.