Executive brief
OP-TEE is an open-source security layer used on Arm-based processors to protect sensitive data and cryptographic operations. A vulnerability in the Hisilicon HPRE hardware accelerator driver allows an attacker to bypass certain cryptographic protections. By measuring the time it takes for the system to process specific requests, an attacker could eventually recover encrypted data (plaintext) that was supposed to remain secret.
Technical details
A timing side-channel vulnerability exists in the Hisilicon HPRE crypto driver's RSA-OAEP decryption implementation. The root cause is the use of a non-constant-time `memcmp()` for label hash verification and a variable-time loop for padding scans, creating multiple distinguishable error paths. An attacker with the ability to submit chosen ciphertexts to a TEE RSA-OAEP decryption interface (e.g., via a Trusted Application) can perform a Manger-style attack. By observing timing differences across 1000-2000 adaptive queries, the attacker can recover the full RSA-OAEP plaintext. This affects platforms using `plat-d06` with `CFG_HISILICON_ACC_V3=y` enabled.
Affected products
- OP-TEE optee_os >= 4.5.0, < 4.11.0
Timeline
- 2026-03-18: other: Received report
- 2026-06-18: patched: Fix published
- 2026-06-18: advisory: Advisory published
- 2026-07-06: disclosed: CVE published to NVD