OP-TEE OS up to 4.10.0 mbedTLS software backend RSA NOPAD Encrypt/RSA NOPAD Decrypt src_len/rsa_len heap-based overflow

Summaryinfo

A vulnerability was found in OP-TEE OS up to 4.10.0. It has been classified as very critical. This impacts the function RSA NOPAD Encrypt/RSA NOPAD Decrypt of the component mbedTLS software backend. This manipulation of the argument src_len/rsa_len causes heap-based overflow. This vulnerability is tracked as CVE-2026-71969. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability classified as very critical was found in OP-TEE OS up to 4.10.0. Affected by this vulnerability is the function RSA NOPAD Encrypt/RSA NOPAD Decrypt of the component mbedTLS software backend. The manipulation of the argument src_len/rsa_len with an unknown input leads to a heap-based overflow vulnerability. The CWE definition for the vulnerability is CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

OP-TEE OS through 4.10.0, fixed in commit 7b8b494, contains a buffer underwrite vulnerability in the RSA NOPAD encrypt and decrypt operations within the mbedTLS software backend and SE050 hardware driver that allows a malicious Trusted Application to corrupt secure-world heap memory by supplying an input length exceeding the RSA modulus size. When src_len exceeds rsa_len, the subtraction expression wraps to a large unsigned value, causing a subsequent memcpy to write attacker-controlled data before the destination buffer in S-EL1 secure-world heap memory.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-71969 since 08/08/2026. The exploitation appears to be easy. The attack can be launched remotely. Additional levels of successful authentication are required for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/10/2026).

Applying the patch 7b8b494e0a324cefec8ed386b7de413b44f1aaf3 is able to eliminate this problem.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-55699). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

• OP-TEE

Name

• OS

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10.0

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Be aware that VulDB is the high quality source for vulnerability data.

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