Vulnerability Details CVE-2026-33662
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 20.2%
CVSS Severity
CVSS v3 Score 7.5
Products affected by CVE-2026-33662
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cpe:2.3:o:linaro:op-tee:3.10.0
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cpe:2.3:o:linaro:op-tee:3.11.0
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cpe:2.3:o:linaro:op-tee:3.12.0
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cpe:2.3:o:linaro:op-tee:3.13.0
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cpe:2.3:o:linaro:op-tee:3.14.0
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cpe:2.3:o:linaro:op-tee:3.15.0
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cpe:2.3:o:linaro:op-tee:3.20
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cpe:2.3:o:linaro:op-tee:3.20.0
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cpe:2.3:o:linaro:op-tee:3.21.0
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cpe:2.3:o:linaro:op-tee:3.22.0
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cpe:2.3:o:linaro:op-tee:3.8.0
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cpe:2.3:o:linaro:op-tee:3.9.0
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cpe:2.3:o:linaro:op-tee:4.0.0
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cpe:2.3:o:linaro:op-tee:4.1.0
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cpe:2.3:o:linaro:op-tee:4.10.0
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cpe:2.3:o:linaro:op-tee:4.2.0
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cpe:2.3:o:linaro:op-tee:4.3.0
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cpe:2.3:o:linaro:op-tee:4.4.0
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cpe:2.3:o:linaro:op-tee:4.5.0
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cpe:2.3:o:linaro:op-tee:4.6.0
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cpe:2.3:o:linaro:op-tee:4.7.0
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cpe:2.3:o:linaro:op-tee:4.8.0
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cpe:2.3:o:linaro:op-tee:4.9.0