CVE-2023-28469: Arm Mali GPU Use-After-Free Vulnerability

CVE-2023-28469 Overview

CVE-2023-28469 is a Use After Free vulnerability discovered in the Arm Mali GPU Kernel Driver. A non-privileged user can make improper GPU processing operations to gain access to already freed memory, potentially leading to sensitive information disclosure. This vulnerability affects devices utilizing Arm's Mali GPU drivers, which are commonly found in mobile devices, embedded systems, and various ARM-based computing platforms.

Critical Impact

Non-privileged attackers with local access can exploit improper GPU processing operations to access freed memory regions, potentially exposing sensitive system information from kernel memory.

Affected Products

• Arm Valhall GPU Kernel Driver r29p0 through r42p0 (before r43p0)
• Arm Avalon GPU Kernel Driver (Architecture Gen5) r41p0 through r42p0 (before r43p0)

Discovery Timeline

• 2023-06-02 - CVE-2023-28469 published to NVD
• 2025-01-08 - Last updated in NVD database

Technical Details for CVE-2023-28469

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a memory corruption flaw that occurs when a program continues to use a pointer after the memory it references has been deallocated. In the context of the Arm Mali GPU Kernel Driver, the vulnerability allows a non-privileged user to manipulate GPU processing operations in a way that triggers access to memory that has already been freed.

The attack requires local access to the system and low privileges to execute. The primary security impact is confidentiality breach, where an attacker could potentially read sensitive information from kernel memory that was previously allocated to other processes or system components. The vulnerability does not directly enable integrity violations or cause system availability issues.

Root Cause

The root cause of CVE-2023-28469 lies in improper memory lifecycle management within the GPU kernel driver. When GPU processing operations are performed, the driver fails to properly validate the state of memory objects before accessing them. This creates a race condition or logic flaw where memory can be freed while still being referenced by ongoing GPU operations.

Specifically, the vulnerability exists in the handling of memory allocations during GPU job submission and completion. When certain sequences of GPU operations are performed by a non-privileged user, the driver may attempt to access memory buffers that have already been released back to the system's memory pool, resulting in a Use After Free condition.

Attack Vector

The attack vector for CVE-2023-28469 requires local access to the target system. An attacker would need to:

1. Obtain local access to a device running a vulnerable version of the Mali GPU Kernel Driver
2. Execute a crafted application that performs specific GPU processing operations
3. Trigger the improper memory handling condition through carefully sequenced GPU API calls
4. Access the freed memory region to read potentially sensitive kernel data

The vulnerability manifests in the GPU memory management subsystem during improper GPU processing operations. Technical details regarding the specific GPU API calls and memory management functions involved can be found in the Arm Security Center Mali GPU Driver Vulnerabilities advisory.

Detection Methods for CVE-2023-28469

Indicators of Compromise

• Unusual GPU driver crashes or kernel panics related to Mali GPU operations
• Anomalous memory access patterns in kernel logs associated with GPU driver activity
• Unexpected application behavior when performing GPU-intensive operations
• Kernel memory corruption detection alerts from system integrity monitoring tools

Detection Strategies

• Monitor for unusual sequences of GPU API calls from unprivileged applications
• Implement kernel-level memory access auditing for the Mali GPU driver subsystem
• Deploy endpoint detection solutions capable of monitoring GPU driver interactions
• Review system logs for Mali GPU driver error messages or warning indicators

Monitoring Recommendations

• Enable verbose logging for the Mali GPU kernel driver to capture memory operation details
• Implement memory corruption detection mechanisms such as KASAN (Kernel Address Sanitizer) where available
• Monitor for applications making excessive or unusual GPU memory allocation requests
• Deploy SentinelOne Singularity Platform for real-time kernel-level threat detection and memory protection

How to Mitigate CVE-2023-28469

Immediate Actions Required

• Update the Arm Mali GPU Kernel Driver to version r43p0 or later
• Audit systems for affected driver versions (r29p0 through r42p0 for Valhall, r41p0 through r42p0 for Gen5 Architecture)
• Restrict local access to systems running vulnerable driver versions until patches can be applied
• Monitor affected systems for signs of exploitation attempts

Patch Information

Arm has released patched versions of the affected GPU kernel drivers. The vulnerability is fixed in version r43p0 for both the Valhall GPU Kernel Driver and the GPU Architecture Gen5 (Avalon) driver. Organizations should coordinate with their device manufacturers or SoC vendors to obtain and deploy the updated driver packages.

For detailed patch information and security advisories, refer to the Arm Security Center Mali GPU Driver Vulnerabilities page.

Workarounds

• Limit local user access to systems with vulnerable Mali GPU drivers
• Disable or restrict access to GPU functionality for non-essential users where operationally feasible
• Implement application whitelisting to prevent unauthorized applications from accessing GPU resources
• Apply defense-in-depth measures including kernel hardening and access controls

# Check current Mali GPU driver version (method varies by platform)
# Example for Android devices with root access:
cat /sys/module/mali_kbase/version

# Verify the driver version is r43p0 or later to confirm patching
# Contact device manufacturer for official update procedures