CVE-2023-3889: Arm Valhall GPU Use-After-Free Vulnerability

CVE-2023-3889 Overview

CVE-2023-3889 is a use after free vulnerability in the Arm Valhall GPU Kernel Driver that allows a local non-privileged user to perform improper GPU memory processing operations. When these operations are carefully prepared, an attacker can gain access to already freed memory, potentially leading to privilege escalation or arbitrary code execution on affected systems.

Critical Impact

Local attackers can exploit improper GPU memory handling to access freed memory, enabling potential privilege escalation from non-privileged user to higher access levels on systems with affected Arm Mali GPUs.

Affected Products

• Arm Valhall GPU Kernel Driver (affected versions)
• Mobile devices and embedded systems utilizing Arm Mali GPUs with Valhall architecture
• Android devices with vulnerable GPU driver versions

Discovery Timeline

• 2023-11-07 - CVE-2023-3889 published to NVD
• 2025-03-24 - Last updated in NVD database

Technical Details for CVE-2023-3889

Vulnerability Analysis

This vulnerability (CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer) manifests in the GPU memory management subsystem of the Arm Valhall GPU Kernel Driver. The flaw allows a local user without elevated privileges to craft specific sequences of GPU memory operations that result in access to memory that has already been deallocated.

The use after free condition occurs when the driver fails to properly track and validate memory references during GPU operations. An attacker can manipulate the timing and sequence of memory allocation and deallocation requests to create a scenario where the driver continues to reference memory blocks that have been returned to the system's free memory pool.

Root Cause

The root cause stems from improper memory boundary operations within the GPU kernel driver. Specifically, the driver does not adequately validate memory state before performing operations, allowing references to persist to memory regions that have been freed. This memory management oversight creates a window where an attacker can potentially reallocate the freed memory with controlled content while the driver still maintains stale references.

Attack Vector

The attack requires local access to the system and does not require elevated privileges. An attacker would need to:

1. Gain local access to a system with an affected Arm Valhall GPU driver
2. Craft a series of GPU memory operations designed to trigger the use after free condition
3. Manipulate the freed memory region to inject malicious content
4. Trigger the driver to access the freed memory, potentially gaining elevated privileges

The vulnerability mechanism involves carefully sequencing GPU memory allocation and deallocation operations to create race conditions or timing windows. When successful, this allows the attacker to manipulate memory contents that the driver incorrectly believes are still valid, potentially leading to code execution with kernel privileges. For detailed technical information, refer to the ARM Security Center Advisory.

Detection Methods for CVE-2023-3889

Indicators of Compromise

• Unusual GPU memory allocation patterns or excessive GPU memory operations from non-graphics applications
• Kernel crash logs or memory corruption errors related to the Mali GPU driver
• Unexpected privilege escalation events following GPU-intensive activity
• System instability or kernel panics associated with GPU driver operations

Detection Strategies

• Monitor for anomalous sequences of GPU-related system calls from unprivileged processes
• Implement kernel-level auditing of GPU driver interactions, particularly memory management functions
• Deploy endpoint detection solutions capable of monitoring driver behavior and memory access patterns
• Analyze process behavior for unusual GPU memory allocation and deallocation patterns

Monitoring Recommendations

• Enable detailed logging for GPU driver operations where supported
• Implement real-time monitoring of kernel memory allocation events related to GPU subsystems
• Configure alerting for privilege escalation attempts following GPU memory operations
• Review system logs for Mali GPU driver error messages or unexpected behavior

How to Mitigate CVE-2023-3889

Immediate Actions Required

• Identify all systems using Arm Valhall GPU kernel drivers and inventory affected devices
• Apply the latest GPU driver updates from Arm or your device manufacturer
• Restrict local access to sensitive systems where feasible until patching is complete
• Monitor affected systems for suspicious activity related to GPU operations

Patch Information

Arm has released security patches addressing this vulnerability. Organizations should update to the latest version of the Valhall GPU Kernel Driver as specified in the ARM Security Center Advisory. Contact your device manufacturer or system integrator for specific patch availability and installation instructions for your platform.

Workarounds

• Limit local user access on systems with vulnerable GPU drivers to trusted users only
• Consider disabling GPU acceleration for untrusted applications where operationally feasible
• Implement strict application control policies to prevent unauthorized applications from accessing GPU resources
• Deploy compensating security controls such as endpoint detection and response (EDR) solutions with kernel-level monitoring capabilities