CVE-2025-20671 is a medium severity vulnerability identified in several MediaTek SoCs (System on Chips), including MT2718, MT6878, MT6897, MT6899, MT6989, MT6991, MT8196, MT8391, MT8676, and MT8678, which are integrated into devices running Android 14.0 and 15.0. The vulnerability arises from an out-of-bounds write condition in the thermal management component of the chipset, caused by a race condition. Specifically, this race condition allows a write operation to occur outside the intended memory boundaries, potentially corrupting adjacent memory regions. Exploitation of this vulnerability requires the attacker to already have System-level privileges on the device, meaning it is a local privilege escalation vulnerability rather than a remote attack vector. No user interaction is required for exploitation once System privileges are obtained. The vulnerability is classified under CWE-787 (Out-of-bounds Write), which typically leads to memory corruption issues that can compromise confidentiality, integrity, and availability of the system. The CVSS v3.1 base score is 6.4, reflecting a medium severity with high impact on confidentiality, integrity, and availability, but with limited attack vector (local) and high attack complexity due to the need for existing System privileges. No known exploits are currently reported in the wild, and a patch has been identified (Patch ID: ALPS09698599), though no direct patch links are provided. This vulnerability could be leveraged by attackers who have already compromised the device at a high privilege level to further escalate privileges, potentially gaining kernel-level or persistent control over the device's thermal management and related subsystems.

For European organizations, the impact of CVE-2025-20671 depends largely on the deployment of devices using the affected MediaTek chipsets running Android 14 or 15. Many consumer and enterprise mobile devices, IoT devices, and embedded systems in Europe utilize MediaTek SoCs due to their cost-effectiveness and performance. An attacker with System privileges could exploit this vulnerability to escalate privileges further, potentially gaining kernel-level access, which could lead to full device compromise, data leakage, or disruption of device functionality. This is particularly concerning for sectors relying on mobile or embedded devices for critical operations, such as telecommunications, manufacturing, healthcare, and public services. The thermal management subsystem is critical for device stability and safety; exploitation could lead to device overheating or denial of service through thermal mismanagement. Although exploitation requires prior System-level access, this vulnerability could be chained with other exploits to achieve full device compromise. The absence of user interaction lowers the barrier for automated or stealthy attacks once initial access is gained. Given the increasing reliance on mobile and embedded devices in European enterprises and critical infrastructure, this vulnerability poses a moderate risk that could facilitate advanced persistent threats or insider attacks.

European organizations should prioritize patching affected devices with the vendor-provided fix (Patch ID: ALPS09698599) as soon as it becomes available. Since the vulnerability requires System privileges for exploitation, organizations should also enforce strict access controls and privilege management on devices using these MediaTek chipsets. Implementing robust endpoint detection and response (EDR) solutions that monitor for privilege escalation attempts and anomalous thermal management behavior can help detect exploitation attempts. Network segmentation and limiting administrative access to devices can reduce the risk of attackers gaining System privileges initially. Additionally, organizations should maintain an inventory of devices using affected MediaTek SoCs and ensure firmware and OS updates are applied promptly. For devices where patching is delayed or not possible, consider deploying runtime protections such as control-flow integrity (CFI) and memory protection mechanisms to mitigate out-of-bounds write impacts. Security teams should also monitor threat intelligence feeds for any emerging exploits targeting this vulnerability and be prepared to respond accordingly. Finally, educating users and administrators about the risks of privilege escalation and enforcing least privilege principles will reduce the attack surface.