CVE-2024-56593
📋 TL;DR
This vulnerability is a NULL pointer dereference in the brcmfmac WiFi driver in the Linux kernel that can cause a kernel panic (system crash) when processing network packets. It affects systems using Broadcom FullMAC wireless chips with specific alignment configurations and high network traffic. The vulnerability requires local network access to trigger but can lead to denial of service.
💻 Affected Systems
- Linux kernel with brcmfmac driver
📦 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 →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
Kernel panic leading to complete system crash and denial of service, requiring physical or remote console access to reboot.
Likely Case
System crash or instability when wireless interface is under heavy load with specific alignment configurations.
If Mitigated
No impact if patched or if system doesn't use affected Broadcom WiFi chips with specific sd_sgentry_align values.
🎯 Exploit Status
Exploitation requires sending specific network traffic patterns to trigger the condition. No public exploit code available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 07c020c6d14d29e5a3ea4e4576b8ecf956a80834, 342f87d263462c2670b77ea9a32074cab2ac6fa1, 34941321b516bd7c6103bd01287d71a1804d19d3, 67a25ea28f8ec1da8894f2f115d01d3becf67dc7, 7522d7d745d13fbeff3350fe6aa56c8dae263571
Vendor Advisory: https://git.kernel.org/stable/c/07c020c6d14d29e5a3ea4e4576b8ecf956a80834
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel package. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable affected WiFi interface
linuxTemporarily disable the Broadcom WiFi interface if not needed
sudo ip link set wlan0 down
sudo nmcli radio wifi off
Reduce network queue limits
linuxLower network interface queue sizes to reduce chance of triggering
sudo ethtool -G wlan0 rx 32 tx 32
🧯 If You Can't Patch
- Isolate affected systems from untrusted networks
- Implement network traffic monitoring for abnormal packet patterns
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if brcmfmac module is loaded: lsmod | grep brcmfmac && uname -rCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is after fix commits and check dmesg for absence of brcmfmac NULL pointer errors📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- NULL pointer dereference in brcmfmac driver
- Oops messages in dmesg
Network Indicators:
- Sudden wireless interface disconnections
- High packet drop rates on WiFi
SIEM Query:
event_source="kernel" AND (message="NULL pointer dereference" OR message="brcmfmac" OR message="kernel panic")🔗 References
- https://git.kernel.org/stable/c/07c020c6d14d29e5a3ea4e4576b8ecf956a80834
- https://git.kernel.org/stable/c/342f87d263462c2670b77ea9a32074cab2ac6fa1
- https://git.kernel.org/stable/c/34941321b516bd7c6103bd01287d71a1804d19d3
- https://git.kernel.org/stable/c/67a25ea28f8ec1da8894f2f115d01d3becf67dc7
- https://git.kernel.org/stable/c/7522d7d745d13fbeff3350fe6aa56c8dae263571
- https://git.kernel.org/stable/c/857282b819cbaa0675aaab1e7542e2c0579f52d7
- https://git.kernel.org/stable/c/dfb3f9d3f602602de208da7bdcc0f6d5ee74af68
- https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html
- https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html
