CVE-2023-53479
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Linux kernel's CXL (Compute Express Link) driver. When the cxl_parse_cfmws() function fails to add a decoder, it improperly accesses freed memory, potentially allowing local attackers to crash the system or execute arbitrary code. This affects systems with CXL hardware running vulnerable Linux kernel versions.
💻 Affected Systems
- Linux kernel
📦 What is this software?
Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →⚠️ Risk & Real-World Impact
Worst Case
Local privilege escalation to kernel-level code execution, potentially leading to complete system compromise.
Likely Case
Kernel panic or system crash causing denial of service.
If Mitigated
No impact if the vulnerable driver is not loaded or if the system lacks CXL hardware.
🎯 Exploit Status
Exploitation requires local access and knowledge of CXL driver internals. The use-after-free occurs in a specific error path.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees (commits: 316db489647b8ddc381682597e89787eac61a278, 4cf67d3cc9994a59cf77bb9c0ccf9007fe916afe, 748fadc08bcbdaf573b34d9784bb3dbd87441dbf)
Vendor Advisory: https://git.kernel.org/stable/c/316db489647b8ddc381682597e89787eac61a278
Restart Required: Yes
Instructions:
1. Update to a patched Linux kernel version from your distribution vendor. 2. Reboot the system to load the new kernel.
🔧 Temporary Workarounds
Disable CXL driver
linuxPrevent loading of the vulnerable CXL driver module
echo 'blacklist cxl_acpi' > /etc/modprobe.d/blacklist-cxl.conf
rmmod cxl_acpi
🧯 If You Can't Patch
- Ensure no CXL hardware is present in the system
- Restrict local user access to systems with CXL hardware
🔍 How to Verify
Check if Vulnerable:
Check if CXL driver is loaded: lsmod | grep cxl_acpi. If loaded and kernel version is unpatched, system is vulnerable.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits or is newer than patched versions from your distribution.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- KASAN or KFENCE error reports mentioning cxl_parse_cfmws
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Search for kernel logs containing 'KASAN: slab-use-after-free' or 'cxl_parse_cfmws'