CVE-2022-49640
📋 TL;DR
This CVE describes a data race vulnerability in the Linux kernel's sysctl subsystem, specifically in the proc_douintvec_minmax() function. Concurrent access to sysctl variables could lead to inconsistent or corrupted values being read or written. This affects all Linux systems using vulnerable kernel versions.
💻 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
System instability, kernel panic, or privilege escalation if race conditions manipulate critical kernel parameters during concurrent access.
Likely Case
Inconsistent system behavior, incorrect parameter values, or minor system instability when multiple processes access sysctl variables simultaneously.
If Mitigated
No impact if proper kernel protections are in place or if concurrent sysctl access is avoided.
🎯 Exploit Status
Exploitation requires local access and concurrent sysctl variable manipulation with specific timing.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Multiple stable kernel versions with fixes: 2d3b559df3ed, 40e0477a7371, b60eddf98b97, e3a2144b3b6b
Vendor Advisory: https://git.kernel.org/stable/c/2d3b559df3ed39258737789aae2ae7973d205bc1
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Check distribution-specific security advisories. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Restrict sysctl access
linuxLimit which users and processes can access sysctl variables to reduce concurrent access opportunities
chmod 600 /proc/sys/*
set kernel.sysctl_writes_strict = 1 in /etc/sysctl.conf
🧯 If You Can't Patch
- Implement strict access controls on /proc/sys directory
- Monitor for unusual sysctl modifications and concurrent access patterns
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare against patched versions in git commits. Vulnerable if using unpatched kernel with concurrent sysctl access.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes one of the fix commits: 2d3b559df3ed, 40e0477a7371, b60eddf98b97, or e3a2144b3b6b📡 Detection & Monitoring
Log Indicators:
- Multiple concurrent sysctl modifications in kernel logs
- Unexpected system parameter changes
Network Indicators:
- None - this is a local kernel vulnerability
SIEM Query:
Search for multiple sysctl write operations from different processes within short time windows