CVE-2022-49236
📋 TL;DR
This is a use-after-free vulnerability in the Linux kernel's BPF subsystem that occurs due to a race condition during module loading. It allows local attackers to potentially crash the kernel or execute arbitrary code. All Linux systems using affected kernel versions with BPF enabled are vulnerable.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to denial of service, or potential privilege escalation to kernel-level code execution.
Likely Case
Kernel crash/panic causing system instability and denial of service.
If Mitigated
No impact if BPF is disabled or kernel is patched.
🎯 Exploit Status
Requires local access and ability to load BPF programs. Race condition exploitation adds complexity.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 0481baa2318cb1ab13277715da6cdbb657807b3f or later
Vendor Advisory: https://git.kernel.org/stable/c/0481baa2318cb1ab13277715da6cdbb657807b3f
Restart Required: No
Instructions:
1. Update Linux kernel to patched version from your distribution vendor. 2. For custom kernels, apply the fix commit and rebuild. 3. No reboot required for livepatch systems; otherwise reboot to load new kernel.
🔧 Temporary Workarounds
Disable BPF subsystem
allDisable the BPF subsystem to prevent exploitation
echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
sysctl -w kernel.unprivileged_bpf_disabled=1
Restrict BPF usage
allLimit BPF program loading to privileged users only
sysctl -w kernel.unprivileged_bpf_disabled=2
🧯 If You Can't Patch
- Implement strict access controls to prevent unprivileged users from loading BPF programs
- Monitor for suspicious BPF program loading attempts and kernel crashes
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if BPF is enabled: uname -r && grep CONFIG_BPF_SYSCALL /boot/config-$(uname -r)Check Version:
uname -rVerify Fix Applied:
Verify kernel version is patched: uname -r should be newer than vulnerable versions. Check if fix commit is present: git log --oneline | grep -i 'btf.*module.*race'📡 Detection & Monitoring
Log Indicators:
- Kernel panic/Oops messages
- BPF program loading failures
- Module loading errors
Network Indicators:
- None - local exploitation only
SIEM Query:
source="kernel" AND ("Oops" OR "panic" OR "BPF" OR "module")