CVE-2026-33662: high-severity vulnerability in OP-TEE optee_os
OP-TEE: RSASSA EMSA- PKCS1-v1_5 underflow in emsa_pkcs1_v1_5_encode()
Published
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.4%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
OP-TEE · optee_osRelated CVEs — OP-TEE optee_os
In the same product, most dangerous first.
CVE-2022-46152HIGHOP-TEE Trusted OS vulnerable to Improper Validation of Array Index in the cleanup_shm_refs functionEPSS 0.5%CVE-2023-41325HIGHOP-TEE double free in shdr_verify_signatureEPSS 0.4%CVE-2026-53763LOWOP-TEE has AES-GCM 32-bit integer overflow in length counters that breaks authentication guaranteeEPSS 0.2%CVE-2026-40290HIGHOP-TEE has a Use-After-Free race in FF-A shared-memory teardownEPSS 0.2%CVE-2026-33317HIGHOP-TEE: PKCS#11 TA out-of-bounds read and memory disclosureEPSS 0.2%CVE-2026-71969HIGHOP-TEE OS 4.10.0 Buffer Underwrite via RSA NOPAD Encrypt/Decrypt OperationsEPSS 0.2%