CVE-2022-50258
📋 TL;DR
This is a stack buffer overflow vulnerability in the Linux kernel's Broadcom WiFi driver (brcmfmac). It allows attackers to read kernel memory beyond allocated buffer boundaries, potentially leading to information disclosure or system crashes. Systems using affected Broadcom WiFi chips with vulnerable kernel versions are at risk.
💻 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 →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 memory corruption leading to privilege escalation, denial of service, or information disclosure of sensitive kernel data.
Likely Case
System crash/panic (kernel oops) causing denial of service, or information disclosure of kernel memory contents.
If Mitigated
No impact if patched or if system doesn't use Broadcom WiFi hardware.
🎯 Exploit Status
Requires local access or ability to interact with WiFi subsystem. Found via syzkaller fuzzing.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits: 0a06cadcc2a0, 17dbe90e13f5, 3a3a5e3f9406, 881f50d76c38, 89243a7b0ea1
Vendor Advisory: https://git.kernel.org/stable/c/0a06cadcc2a0044e4a117cc0e61436fc3a0dad69
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 Broadcom WiFi
linuxDisable or blacklist brcmfmac driver if WiFi not needed
echo 'blacklist brcmfmac' >> /etc/modprobe.d/blacklist.conf
rmmod brcmfmac
🧯 If You Can't Patch
- Disable WiFi functionality if not required
- Restrict physical and network access to prevent local exploitation
🔍 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 brcmfmac errors📡 Detection & Monitoring
Log Indicators:
- Kernel panic/oops messages
- KASAN stack-out-of-bounds reports in dmesg
- brcmfmac driver crash logs
Network Indicators:
- Unusual WiFi disconnections or initialization failures
SIEM Query:
kernel: *KASAN* OR kernel: *stack-out-of-bounds* OR kernel: *brcmfmac* AND (panic OR oops OR BUG)🔗 References
- https://git.kernel.org/stable/c/0a06cadcc2a0044e4a117cc0e61436fc3a0dad69
- https://git.kernel.org/stable/c/17dbe90e13f52848c460d253f15b765038ec6dc0
- https://git.kernel.org/stable/c/3a3a5e3f94068cd562d62a57da6983c8cd07d53c
- https://git.kernel.org/stable/c/881f50d76c3892262730ddf5c894eb00310e736c
- https://git.kernel.org/stable/c/89243a7b0ea19606ba1c2873c9d569026ccb344f
- https://git.kernel.org/stable/c/ba166e0ebdde3dfa833f0a3edaf2b2934d4a87f7
- https://git.kernel.org/stable/c/d481fd6064bf215d7c5068e15aa390c3b16c9cd0
- https://git.kernel.org/stable/c/d6ef66194bb4a6c18f5b9649bf62597909b040e4
