Secure Service Wrapper Vulnerabilities in ESF-IDF

Executive Summary

CVE-2026-45328 is a critical security vulnerability in the ESP-TEE component of Espressif's ESP-IDF framework, which bridges calls from user applications (REE) to Trusted Execution Environment (TEE) protected hardware peripherals and security features.

The vulnerability arises because several secure-service wrappers in esp_secure_services.c and esp_secure_services_iram.c only partially validate caller-supplied pointer arguments. This incomplete validation allows out-of-bounds writes due to unchecked output data pointers, struct context pointers, and buffer end addresses, as well as failure to handle 32-bit address-space overflow.

An unprivileged REE application can exploit this flaw to cause the ESP-TEE hardware peripherals to write attacker-controlled data into TEE-resident DRAM, breaking the isolation boundary between REE and TEE. This can lead to memory corruption, denial of service, system crashes, or even arbitrary code execution within the TEE, granting elevated privileges.

The vulnerability affects Espressif SoCs with ESP-TEE support, including ESP32-C5, ESP32-C6, ESP32-C61, and ESP32-H2, and has been patched in ESP-IDF versions 5.5.5 and 6.0.1.

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Impact Analysis

This vulnerability can have severe impacts including unauthorized access and control over the Trusted Execution Environment (TEE) by an attacker with only local code execution privileges in the REE.

• Breaks the isolation boundary between the REE and TEE, allowing attacker-controlled data to be written into secure memory.
• Potential arbitrary code execution within the TEE, leading to privilege escalation.
• Memory corruption in the TEE, which can cause denial of service or system crashes.
• Compromise of critical security features such as attestation, OTA updates, and secure storage.

Because the vulnerability allows an attacker to manipulate secure hardware peripherals and memory, it poses a high risk to the confidentiality, integrity, and availability of the system.

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Detection Guidance

Detection of this vulnerability involves monitoring for memory corruption or abnormal behavior in the ESP-TEE component, especially related to secure service calls bridging user applications to TEE-protected hardware peripherals.

The updated code introduces aborts and error messages when heap corruption is detected via the MULTI_HEAP_ASSERT macro, which now prints the memory address of corruption and aborts execution. This can help detect memory corruption issues during heap operations in the TEE.

While no explicit detection commands are provided, you can monitor system logs for abort messages or errors related to heap assertions in the ESP-TEE component.

Additionally, verifying the ESP-IDF version running on your device can help detect if the vulnerable version is in use. Versions prior to 5.5.5 and 6.0.1 are vulnerable.

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Mitigation Strategies

The primary mitigation step is to update the ESP-IDF framework to a patched version, specifically version 5.5.5 or 6.0.1 or later, where the vulnerability has been fixed.

The fix includes adding comprehensive input validation for all TEE service calls, relocating the secure service call dispatch table from TEE DRAM to TEE IRAM to make it immutable, and improving error handling to abort on memory corruption.

There is no runtime workaround for this issue, so applying the patch or upgrading to a fixed release is essential.

Users should also audit their applications to ensure they do not pass unchecked pointers or buffers to the esp_tee component.

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Compliance Impact

CVE-2026-45328 is a critical vulnerability in the ESP-TEE component of Espressif's ESP-IDF framework that allows an unprivileged user application to break the isolation boundary between the Rich Execution Environment (REE) and the Trusted Execution Environment (TEE). This can lead to arbitrary code execution within the TEE, memory corruption, denial of service, and system crashes.

Because the vulnerability compromises the confidentiality, integrity, and availability of the secure environment, it poses significant risks to the security of sensitive data and operations handled by the TEE. Such a compromise can impact compliance with common standards and regulations like GDPR and HIPAA, which require strong protections for data confidentiality and integrity.

Specifically, the ability to execute arbitrary code or corrupt memory in the TEE could lead to unauthorized access or modification of protected data, violating data protection requirements. The critical severity (CVSS 9.3) and the nature of the vulnerability highlight the importance of applying the patches provided in versions 5.5.5 and 6.0.1 to maintain compliance.

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