CVE-2021-47602
📋 TL;DR
A vulnerability in the Linux kernel's mac80211 subsystem allows uninitialized memory access when processing non-QoS nullfunc packets for admission control. This could lead to kernel memory disclosure or system instability. Systems using affected Linux kernel versions with wireless networking are affected.
💻 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 →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 disclosure leading to information leakage or potential privilege escalation if combined with other vulnerabilities.
Likely Case
System instability, crashes, or denial of service on wireless interfaces.
If Mitigated
Minimal impact with proper kernel hardening and wireless interface isolation.
🎯 Exploit Status
Exploitation requires sending crafted wireless packets to target system.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in stable kernel versions via provided git commits
Vendor Advisory: https://git.kernel.org/stable/c/42d08e97b196479f593499e887a9ab81446a34b9
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Reboot system. 3. Verify kernel version is updated.
🔧 Temporary Workarounds
Disable wireless interfaces
linuxTemporarily disable vulnerable wireless interfaces
sudo ip link set wlan0 down
🧯 If You Can't Patch
- Implement network segmentation to isolate wireless networks
- Use wired networking instead of wireless where possible
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions in git commitsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated beyond patched commits📡 Detection & Monitoring
Log Indicators:
- Kernel panics
- Wireless interface errors in dmesg
- System crashes
Network Indicators:
- Unusual wireless packet patterns
- Malformed nullfunc packets
SIEM Query:
source="kernel" AND ("mac80211" OR "admission control") AND (error OR panic)🔗 References
- https://git.kernel.org/stable/c/42d08e97b196479f593499e887a9ab81446a34b9
- https://git.kernel.org/stable/c/46b9e29db2012a4d2a40a26101862e002ccf387b
- https://git.kernel.org/stable/c/69f054d6642c8f6173724ce17e7ee3ff66b8f682
- https://git.kernel.org/stable/c/d5e568c3a4ec2ddd23e7dc5ad5b0c64e4f22981a
- https://git.kernel.org/stable/c/eed897a22230e3231a740eddd7d6d95ba476625f
- https://git.kernel.org/stable/c/42d08e97b196479f593499e887a9ab81446a34b9
- https://git.kernel.org/stable/c/46b9e29db2012a4d2a40a26101862e002ccf387b
- https://git.kernel.org/stable/c/69f054d6642c8f6173724ce17e7ee3ff66b8f682
- https://git.kernel.org/stable/c/d5e568c3a4ec2ddd23e7dc5ad5b0c64e4f22981a
- https://git.kernel.org/stable/c/eed897a22230e3231a740eddd7d6d95ba476625f
