CVE-2022-50490
📋 TL;DR
A race condition vulnerability in the Linux kernel's BPF subsystem allows improper error handling during hash table operations. When htab_lock_bucket() returns -EBUSY, the system may skip elements or expose kernel memory to userspace. This affects systems running vulnerable Linux kernel versions with BPF enabled.
💻 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 memory disclosure leading to information exposure, potential privilege escalation, or system instability.
Likely Case
Application crashes, data corruption, or denial of service due to improper memory access.
If Mitigated
Minimal impact if BPF is disabled or systems are patched; applications receive proper -EBUSY errors.
🎯 Exploit Status
Requires local access and BPF privileges; race condition exploitation can be challenging.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 0e13425104903970a5ede853082d3bbb4edec6f3, 4f1f39a8f1ce1b24fee6852d7dcd704ce7c4334d, 66a7a92e4d0d091e79148a4c6ec15d1da65f4280, or 6bfee6eb3d6b96ae730a542909dd22b5f9f50d58
Vendor Advisory: https://git.kernel.org/stable/c/0e13425104903970a5ede853082d3bbb4edec6f3
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify kernel version matches patched release.
🔧 Temporary Workarounds
Disable BPF subsystem
linuxRemove BPF capabilities to prevent exploitation
echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
Remove CAP_BPF from user capabilities
Restrict BPF privileges
linuxLimit which users can use BPF features
sysctl -w kernel.unprivileged_bpf_disabled=1
Use capability bounding sets to remove CAP_BPF
🧯 If You Can't Patch
- Restrict user access to systems with vulnerable kernels
- Implement strict capability management to prevent unauthorized BPF usage
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions from git commits; verify BPF is enabled in kernel configCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes one of the fixing commits; test BPF hash table operations return proper -EBUSY errors📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- BPF subsystem errors in dmesg
- Application crashes related to BPF operations
Network Indicators:
- Not applicable - local vulnerability
SIEM Query:
Search for: 'kernel: BPF error' OR 'kernel: htab_lock_bucket failed' OR unexpected process crashes with BPF capabilities