MediaTek Power HAL CVE-2026-20509

Exploitation requires the attacker to already control a process running with Android System-level privileges (equivalent to UID=1000 or a System-signed application context) - this is not a default-user or app-sandbox permission level. The vulnerable code path is in the Power HAL, which is invoked through Android's HAL interface layer; reaching it from a lower privilege context would require a separate, prior privilege escalation. No user interaction is needed once System privilege is obtained. The constraint that limits exploitation is the System privilege precondition: standard third-party applications, including those with root or shell access granted by the user, cannot directly interact with the Power HAL without first having been granted System-level trust by the platform. Exploitation is further constrained to local (physical or software) access - no network vector exists.

CVSS 6.7 accurately reflects the constrained threat model: exploitation is local-only and requires the attacker to already control a process running at Android System privilege - a non-trivial precondition that substantially narrows the attack surface. SSVC rates automatable as no, consistent with this prerequisite chain. However, SSVC technical impact is rated total, meaning a successful exploit achieves full C:H/I:H/A:H - likely kernel or root-level code execution on the device. The real-world risk materialises in chained attack scenarios where an attacker first compromises a System-privileged process (e.g., via another vulnerability) and then uses this flaw for full device takeover. No CISA KEV listing and no public POC are noted, keeping immediate exploitation risk low. The breadth of affected chipsets (40 models across MediaTek's portfolio) means patch deployment across Android OEMs will be slow and uneven, extending the window of exposure for devices that do not receive timely OEM updates.

An attacker who has already compromised a System-privileged Android process - for example, by exploiting a separate vulnerability in a System service or a pre-installed app - crafts an oversized input to the Power HAL interface, triggering the stack-based buffer overflow. Overwriting the stack frame allows control of the instruction pointer, enabling arbitrary code execution at an elevated privilege level (root or kernel). No public proof-of-concept is known, so this scenario currently requires bespoke exploit development as part of a multi-stage attack chain.