CVE-2026-102709 in ThreadX
Summary
by MITRE • 09/29/2026
Improper validation of non-secure (NS) pointers in multiple TrustZone-M non-secure callable (NSC) entry functions allows an attacker executing in the non-secure world to supply pointers to secure memory. The secure firmware subsequently dereferences these attacker-controlled pointers without verifying that they reference non-secure memory, resulting in unintended disclosure of secure memory contents. This violates the isolation guarantees provided by Arm TrustZone-M and can be leveraged as a memory disclosure or corruption primitive that may enable recovery of sensitive cryptographic material.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 09/29/2026
The vulnerability described constitutes a critical failure in boundary enforcement within ARM TrustZone-M enabled systems, specifically targeting the interface between non-secure and secure execution environments through Non-Secure Callable entry functions. In these architectures, the system is partitioned into two distinct worlds: the non-secure world, which typically runs standard operating systems or untrusted applications, and the secure world, which hosts trusted firmware responsible for handling sensitive operations such as cryptographic key management and authentication. The core technical flaw lies in the improper validation of memory pointers passed from the non-secure world to these NSC entry functions. When a non-secure application invokes a service provided by the secure firmware, it passes arguments including memory addresses that point to buffers containing data or instructions for processing. A robust implementation must rigorously verify that every pointer supplied by the non-secure context actually resides within the designated non-secure memory region and does not overlap with any address space allocated to the secure world. However, in this specific instance, the secure firmware fails to perform adequate bounds checking on these NS pointers before dereferencing them. This oversight allows an attacker operating at a lower privilege level in the non-secure domain to craft malicious inputs that specify memory addresses belonging to the secure partition.
From a technical perspective, this flaw represents a classic violation of isolation principles where trust boundaries are not strictly enforced during inter-process or cross-world communication. The absence of pointer validation means that when the secure firmware attempts to read from or write to the provided address, it inadvertently accesses physical or virtual memory locations reserved for its own exclusive use. This behavior directly maps to CWE-20 Improper Input Validation and more specifically aligns with CWE-787 Out-of-bounds Write if the operation involves writing data back to the caller's buffer but targets secure addresses due to miscalculation, though in this case, it is primarily an out-of-bounds read scenario leading to information leakage. The operational impact of such a vulnerability is severe because it effectively neutralizes the hardware-enforced isolation that TrustZone-M provides. By successfully supplying pointers into secure memory space, the attacker gains the ability to exfiltrate data stored within the trusted execution environment. This can include sensitive cryptographic material such as private keys, session tokens, or user credentials that are protected by design from non-secure access. The disclosure of these assets undermines the fundamental security model of the device, potentially allowing for further exploitation chains where recovered secrets facilitate decryption of communications or impersonation of legitimate users.
Furthermore, this vulnerability can be leveraged not only as a passive information disclosure primitive but also potentially as an active corruption mechanism depending on how the secure firmware utilizes the data retrieved from these maliciously pointed addresses. If the firmware processes input fetched from attacker-controlled locations that happen to map into secure memory regions containing critical control structures or configuration parameters, it could lead to unintended state modifications within the trusted environment. This aligns with ATT&CK techniques related to privilege escalation and defense evasion, specifically those involving exploitation of trust boundaries and manipulation of system resources across security domains. The ability to read secure memory contents breaks confidentiality guarantees, while any potential for writing through similar unchecked mechanisms would compromise integrity. Such flaws are particularly dangerous in IoT devices, mobile phones, and embedded systems where TrustZone-M is commonly deployed to protect boot processes and hardware-based root of trust components.
Mitigation strategies must focus on rigorous input validation at the interface boundary between non-secure and secure worlds. Developers implementing NSC functions must ensure that all pointers received from the non-secure context are validated against a predefined memory map or region descriptor table maintained by the system monitor or hypervisor layer. This involves checking each pointer to confirm it falls within the allowed range of non-secure RAM addresses before any dereferencing operation occurs. Additionally, implementing strict access control checks that verify permissions associated with the target address can prevent accidental reads from protected regions. It is also advisable to utilize hardware features provided by ARM Cortex-M processors, such as Memory Protection Unit (MPU) configurations, which can be leveraged in conjunction with software validation to create defense-in-depth layers. Regular security audits and static analysis focused on inter-processor communication patterns should be conducted to identify similar vulnerabilities across other NSC entry points. Finally, adopting secure coding practices that assume all external inputs are hostile until proven otherwise is essential for maintaining the integrity of TrustZone-M deployments in production environments.