CVE-2023-4211: Arm 5th Gen GPU Driver Use-After-Free Flaw

CVE-2023-4211 Overview

CVE-2023-4211 is a Use-After-Free vulnerability affecting multiple Arm Mali GPU kernel drivers. A local non-privileged user can make improper GPU memory processing operations to gain access to already freed memory. This vulnerability allows attackers to potentially read sensitive information from memory that has been deallocated, posing significant risks in environments where the affected GPU drivers are deployed.

Critical Impact

This vulnerability is actively exploited in the wild and has been added to CISA's Known Exploited Vulnerabilities (KEV) catalog, requiring immediate attention from organizations using affected Arm Mali GPU drivers.

Affected Products

• Arm 5th Gen GPU Architecture Kernel Driver
• Arm Bifrost GPU Kernel Driver
• Arm Midgard GPU Kernel Driver
• Arm Valhall GPU Kernel Driver

Discovery Timeline

• October 1, 2023 - CVE-2023-4211 published to NVD
• October 23, 2025 - Last updated in NVD database

Technical Details for CVE-2023-4211

Vulnerability Analysis

CVE-2023-4211 is classified as CWE-416 (Use After Free), a memory corruption vulnerability that occurs when a program continues to use a pointer after the memory it references has been freed. In the context of Arm Mali GPU kernel drivers, this flaw allows a local non-privileged user to manipulate GPU memory processing operations in a way that grants access to memory regions that have already been deallocated.

The vulnerability exists in the kernel-level GPU driver components, which manage memory allocation and deallocation for GPU operations. When exploited, an attacker can potentially read sensitive data that remains in the freed memory blocks, leading to information disclosure. Since the attack vector is local, an attacker would need some form of access to the target system, but importantly, no elevated privileges are required to trigger the vulnerability.

Root Cause

The root cause of this vulnerability lies in improper memory management within the Arm Mali GPU kernel drivers. Specifically, the drivers fail to properly validate or handle memory references after deallocation, allowing subsequent operations to access memory that has already been freed. This represents a fundamental flaw in the memory lifecycle management of GPU resources, where pointers to freed memory are not adequately nullified or validated before use.

Attack Vector

The attack vector for CVE-2023-4211 is local, meaning an attacker must have some level of access to the target system to exploit the vulnerability. The attack requires low complexity and low privileges, with no user interaction needed. An attacker can craft malicious GPU memory operations that trigger the use-after-free condition, potentially gaining access to sensitive information stored in previously allocated memory regions.

The exploitation scenario typically involves:

1. A local attacker identifying a code path that leads to memory being freed
2. Timing the allocation of new data to occupy the freed memory space
3. Triggering a reference to the original pointer, which now points to the new data or stale sensitive information

Since this vulnerability has been confirmed as actively exploited in the wild and is listed in CISA's KEV catalog, organizations should treat remediation as a high priority.

Detection Methods for CVE-2023-4211

Indicators of Compromise

• Unusual GPU memory allocation patterns or excessive memory operations from non-privileged processes
• Unexpected access attempts to GPU driver interfaces from applications that typically don't require GPU resources
• System instability or crashes related to GPU memory operations
• Evidence of local privilege escalation attempts following GPU-related anomalies

Detection Strategies

• Monitor system logs for anomalous GPU driver behavior, including repeated memory allocation/deallocation cycles
• Implement kernel-level auditing to detect suspicious ioctl calls to GPU driver interfaces
• Deploy endpoint detection solutions capable of identifying use-after-free exploitation patterns
• Review application behavior for unexpected GPU driver interactions

Monitoring Recommendations

• Enable enhanced logging for GPU driver operations where supported by the platform
• Implement behavioral analysis to detect memory corruption exploitation attempts
• Monitor for known exploitation toolkits targeting Arm Mali GPU vulnerabilities
• Establish baselines for normal GPU memory usage to identify anomalous patterns

How to Mitigate CVE-2023-4211

Immediate Actions Required

• Review and update all Arm Mali GPU kernel drivers to the latest patched versions available from Arm
• Consult the Arm Security Center Mali GPU Driver Vulnerabilities page for specific patch information
• Prioritize patching on systems with untrusted local users or multi-tenant environments
• Implement additional access controls to limit which processes can interact with GPU drivers

Patch Information

Arm has released security updates to address this vulnerability. Organizations should consult the Arm Security Center for detailed information on affected driver versions and available patches. Given that this vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, federal agencies are required to remediate within mandated timeframes, and all organizations should treat this as a priority update.

Workarounds

• Restrict local access to systems running affected GPU drivers to trusted users only
• Implement application allowlisting to limit which programs can interact with GPU resources
• Consider disabling or restricting access to affected GPU driver functionality in high-security environments until patches can be applied
• Deploy endpoint protection solutions with memory exploitation detection capabilities