{"id":"CVE-2026-33662","summary":"OP-TEE: RSASSA EMSA- PKCS1-v1_5 underflow in emsa_pkcs1_v1_5_encode()","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.","aliases":["GHSA-4cf8-v5g3-73gr"],"modified":"2026-07-08T08:11:18.089870553Z","published":"2026-04-24T18:13:28.529Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-190"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33662.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33662.json"},{"type":"ADVISORY","url":"https://github.com/OP-TEE/optee_os/security/advisories/GHSA-4cf8-v5g3-73gr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33662"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/op-tee/optee_os","events":[{"introduced":"023e33656e2c9557ce50ad63a98b2e2c9b51c118"},{"last_affected":"753afbbee1682f5d16fd30e87b31058a4fd4f4b8"}],"database_specific":{"extracted_events":[{"introduced":"3.8.0"},{"last_affected":"4.10"}],"source":"AFFECTED_FIELD"}}],"versions":["4.10.0","4.10.0-rc1","4.9.0","4.9.0-rc1","4.8.0","4.8.0-rc1","4.7.0","4.7.0-rc1","4.6.0","4.6.0-rc1","4.5.0","4.5.0-rc1","4.4.0","4.4.0-rc1","4.3.0","4.3.0-rc1","4.2.0","4.2.0-rc1","4.1.0","4.1.0-rc1","4.0.0","4.0.0-rc1","3.22.0","3.22.0-rc1","3.21.0","3.21.0-rc1","3.20.0","3.20.0-rc1","3.19.0","3.19.0-rc1","3.18.0","3.18.0-rc1","3.17.0","3.17.0-rc1","3.16.0","3.15.0","3.15.0-rc1","3.14.0","3.14.0-rc1","3.13.0","3.13.0-rc1","3.12.0","3.12.0-rc1","3.11.0","3.11.0-rc1","3.10.0","3.10.0-rc1","3.9.0","3.9.0-rc1","3.8.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/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"}]}