Arm Mali GPU Kernel Driver Use-After-Free Vulnerability (CVE-2022-38181) Technical Analysis and Hardening Guide

1. Vulnerability Overview & Root Cause

This vulnerability (CVE-2022-38181) is a critical Use-After-Free (UAF) flaw within the Arm Mali GPU kernel driver's memory management subsystem. The root cause lies in the improper handling of reference counting and page mapping during GPU memory allocation and deallocation operations. When the driver fails to properly track or invalidate mappings of freed memory pages, it allows subsequent operations to access and modify memory that has already been returned to the system allocator.

2. Exploitation Mechanics & Attack Scenario

An attacker operating in user space (such as a non-privileged application) can trigger this vulnerability by invoking specific sequence of ioctl system calls designed to manipulate GPU memory mappings. By exploiting the race condition or reference counting flaw, the attacker ensures that a specific memory page is freed while the GPU MMU page tables still retain a valid reference to it. The attacker then sprays the kernel heap to reclaim the freed page with sensitive kernel structures (e.g., credentials or function pointers) and modifies them via the dangling GPU mapping, achieving local privilege escalation (LPE) to root.

3. Infrastructure & Business Impact

As a vulnerability listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, CVE-2022-38181 has been actively exploited in the wild to target mobile and embedded ecosystems. Successful exploitation completely compromises the confidentiality, integrity, and availability of the affected device. In an enterprise environment, compromised mobile endpoints can serve as an initial entry point for lateral movement, credential harvesting, and unauthorized access to corporate networks and cloud assets.