Bug 2497453 (CVE-2026-44362)

Summary: CVE-2026-44362 optee: OP-TEE: Subkey rollback protection bypass allows loading of unauthorized Trusted Applications
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in OP-TEE, a Trusted Execution Environment (TEE) for Arm Cortex-A cores. This vulnerability allows a local attacker to bypass subkey rollback protection due to a failure in propagating versioning data during the Trusted Application (TA) loading process. Specifically, the system incorrectly processes subkey headers, preventing the rollback database from advancing. This enables the successful loading of Trusted Applications signed with revoked or older subkey versions, potentially compromising the integrity of the secure environment.
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Bug Depends On: 2497692    
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Description OSIDB Bzimport 2026-07-06 20:01:56 UTC 
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.