CVE-2023-6241
📋 TL;DR
This CVE describes a use-after-free vulnerability in multiple Arm Mali GPU kernel drivers that allows a local non-privileged user to exploit a race condition for improper memory operations. If successfully exploited, it could lead to privilege escalation or system compromise. The vulnerability affects various Arm GPU driver versions across Midgard, Bifrost, Valhall, and 5th Gen GPU architectures.
💻 Affected Systems
- Arm Ltd Midgard GPU Kernel Driver
- Arm Ltd Bifrost GPU Kernel Driver
- Arm Ltd Valhall GPU Kernel Driver
- Arm Ltd Arm 5th Gen GPU Architecture Kernel Driver
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Local privilege escalation to kernel-level access, potentially leading to full system compromise, data theft, or persistent backdoor installation.
Likely Case
Local privilege escalation allowing attackers to gain elevated privileges on the affected system.
If Mitigated
Limited impact if proper access controls and privilege separation are implemented, though kernel-level vulnerabilities remain serious.
🎯 Exploit Status
Exploitation requires local access and careful memory preparation. Race condition exploitation adds complexity.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after the affected ranges: Midgard > r32p0, Bifrost > r25p0, Valhall > r25p0 and > r46p0, 5th Gen > r46p0
Vendor Advisory: https://developer.arm.com/Arm%20Security%20Center/Mali%20GPU%20Driver%20Vulnerabilities
Restart Required: Yes
Instructions:
1. Check current GPU driver version. 2. Obtain updated driver from Arm or device manufacturer. 3. Install updated driver package. 4. Reboot system to load new kernel driver.
🔧 Temporary Workarounds
Restrict local user access
allLimit local user accounts and implement strict access controls to reduce attack surface
Implement SELinux/AppArmor policies
linuxUse mandatory access control to restrict GPU driver access
# Configure SELinux policies for GPU driver
# audit2allow to create custom policies if needed
🧯 If You Can't Patch
- Implement strict user access controls and privilege separation
- Monitor for suspicious local privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check GPU driver version: cat /sys/class/misc/mali0/device/driver/version or similar driver-specific locationCheck Version:
cat /sys/class/misc/mali0/device/driver/version 2>/dev/null || dmesg | grep -i maliVerify Fix Applied:
Verify driver version is outside affected ranges after update📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages related to Mali driver
- Unexpected privilege escalation attempts
- Suspicious GPU driver access patterns
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("mali" OR "GPU") AND ("oops" OR "panic" OR "segfault")