Vulnerability Report

CVE-2026-33662

Title: OP-TEE Integer Overflow in RSA encoding leading to Denial of Service

Memory Corruption

Proof Of Concept

No public PoC currently indexed for CVE-2026-33662.

CWE Category CWE-190

Published Date Apr 24, 2026

Modified Date Jun 05, 2026

Exploit Status Not Found

Score 7.5 CVSS v3.1

Exploit Probability (EPSS)

0.10%

Vulnerability Summary

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.

Impacted Vendors

linaro 1

trustedfirmware 1

Reference Links

https://github.com/OP-TEE/optee_os/security/advisories/GHSA-4cf8-v5g3-73gr

CVSS v3.1

Source Entity [email protected]

Severity HIGH

7.5

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns