CVE-2026-44362
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
In OP-TEE from version 3.20.0 to 4.10.0, a vulnerability exists in the subkey rollback protection mechanism. The `shdr_load_pub_key()` function fails to assign the subkey version to the runtime structure, leaving the version field at zero. Consequently, the version update check (`check_update_version()`) does not record the correct version, allowing Trusted Applications (TAs) signed with older or revoked subkeys to load successfully.
Risk Assessment
The organization may lose control over the integrity of trusted applications, as an attacker could use revoked subkeys to execute unauthorized code within the TEE environment. This could lead to a breach of confidentiality and integrity of data protected by TrustZone.
Recommendation
Immediately update OP-TEE to version 4.11.0 or later, which contains the fix. No workarounds are available.
Original NVD description (English source)
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 3.20.0 and prior to version 4.11.0, a vulnerability in OP-TEE’s subkey rollback protection allows the use of revoked or older subkey versions because the system fails to propagate versioning data during the Trusted Application (TA) loading process. In `core/crypto/signed_hdr.c`, the function `shdr_load_pub_key()` parses subkey headers but does not assign the `subkey_version` to the runtime `shdr_pub_key` structure. As a result, the `key->version` field remains at zero regardless of the version specified in the header. When `ree_fs_ta_open()` in `core/kernel/ree_fs_ta.c` calls `check_update_version()`, it passes this zeroed version to the rollback database. Because the database never receives a non-zero version to record, it never advances, effectively bypassing the rollback check and allowing TAs signed with downgraded subkey chains to load successfully. This impacts OP-TEE mainline configurations that utilize subkey-based signing chains for Trusted Application (TA) authentication. Version 4.11.0 contains a patch. No known workarounds are available.