OP-TEE Vulnerability Exposes TrustZone to OOB Reads, Crashes

The National Vulnerability Database has disclosed CVE-2026-33317, a high-severity vulnerability affecting OP-TEE versions 3.13.0 through 4.10.0. OP-TEE is a Trusted Execution Environment (TEE) designed to run alongside a non-secure Linux kernel on Arm Cortex-A cores utilizing TrustZone technology. This flaw, a missing check in entry_get_attribute_value() within the PKCS#11 TA, allows for out-of-bounds reads from the PKCS#11 TA heap or system crashes.

Specifically, a crafted template parameter can trick the PKCS11_CMD_GET_ATTRIBUTE_VALUE function into reading up to 7 bytes beyond the template buffer and writing beyond it with PKCS#11 object attribute values. This isn’t just a denial-of-service; an out-of-bounds read in a TEE context is critical. It can lead to information disclosure from the secure world, potentially exposing sensitive data or even enabling further exploitation for privilege escalation within the TEE.

The CVSS score of 8.7 (High) underscores the severity. For defenders, the implications are clear: compromise of the TEE fundamentally undermines the security guarantees of the entire system. Patches are anticipated in version 4.11.0, with specific commits already identified. Organizations deploying Arm-based systems relying on OP-TEE must prioritize updating to mitigate this significant risk.