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CVE-2026-44362

OP-TEE's subkey rollback protection can be bypassed with older subkey versions

5.5 Medium

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.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
High
Availability
None

Exploit likelihood

0.18%Unchanged since Jul 7, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.5

OP-TEE's subkey rollback protection can be bypassed with older subkey versions

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.

Record
CVE-2026-44362
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Weakness
CWE-285
Updated
2026-11-02
EUVDEUVD-2026-41911 5.5

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.

Record
EUVD-2026-41911
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02
NVD 5.5

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.

Record
CVE-2026-44362
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Weakness
CWE-285
Updated
2026-11-02
OSV 5.5

OP-TEE's subkey rollback protection can be bypassed with older subkey versions

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.

Record
CVE-2026-44362
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Weakness
CWE-285
Updated
2026-11-02
OSVDEBIAN-CVE-2026-44362 5.5

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.

Record
DEBIAN-CVE-2026-44362
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02
OSVUBUNTU-CVE-2026-44362 5.5

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.

Record
UBUNTU-CVE-2026-44362
CVSS 3.1
5.5 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
optee-os
Debian:13
All versions, plus listed versions
4.10.0-14.10.0-24.5.0-24.7.0-14.8.0-14.9.0-1
None known
optee-os
Ubuntu:25.10
All versions, plus listed versions
4.5.0-14.5.0-24.7.0-1
None known
optee-os
Ubuntu:26.10
All versions, plus listed versions
4.8.0-14.10.0-14.10.0-2
None known
optee-os
Ubuntu:26.04:LTS
All versions, plus listed versions
4.7.0-14.8.0-1
None known

History

History
RecordedChangedSources
first indexedCVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-44362 is a medium vulnerability (CVSS 5.5) in Trustedfirmware Op-tee, published July 6, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.18%, the 7th percentile. No source names a fixed version.

References

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