{"id":"UBUNTU-CVE-2026-33662","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. From 3.8.0 to 4.10, in the function emsa_pkcs1_v1_5_encode() in core/drivers/crypto/crypto_api/acipher/rsassa.c, the amount of padding needed, \"PS size\", is calculated by subtracting the size of the digest and other fields required for the EMA-PKCS1-v1_5 encoding from the size of the modulus of the key. By selecting a small enough modulus, this subtraction can overflow. The padding is added as a string of 0xFF bytes with a call to memset(), and an underflowed integer will cause the memset() call to overwrite until OP-TEE crashes. This only affects platforms registering RSA acceleration.","modified":"2026-05-20T16:25:29.909071491Z","published":"2026-04-24T19:17:00Z","upstream":["CVE-2026-33662"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-33662"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-33662"},{"type":"REPORT","url":"https://github.com/OP-TEE/optee_os/security/advisories/GHSA-4cf8-v5g3-73gr"}],"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_name":"optee-os","binary_version":"4.7.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33662.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_name":"optee-os","binary_version":"4.8.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33662.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}