{"id":"UBUNTU-CVE-2026-44362","details":"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-\u003eversion` 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.","modified":"2026-07-09T17:15:58.138132909Z","published":"2026-07-06T20:16:00Z","upstream":["CVE-2026-44362"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-44362"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-44362"},{"type":"REPORT","url":"https://github.com/OP-TEE/optee_os/security/advisories/GHSA-fhcg-pp56-8v75"}],"affected":[{"package":{"name":"optee-os","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/optee-os?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.5.0-1","4.5.0-2","4.7.0-1"],"ecosystem_specific":{"binaries":[{"binary_version":"4.7.0-1","binary_name":"optee-os"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44362.json"}},{"package":{"name":"optee-os","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/optee-os?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.7.0-1","4.8.0-1"],"ecosystem_specific":{"binaries":[{"binary_version":"4.8.0-1","binary_name":"optee-os"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44362.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N"},{"type":"Ubuntu","score":"medium"}]}