CVE-2022-50477
📋 TL;DR
This is a memory leak vulnerability in the Linux kernel's RTC (Real-Time Clock) subsystem. When dev_set_name() fails during device allocation, the previously allocated rtc_device structure is not properly freed, leading to kernel memory exhaustion over time. This affects Linux systems using RTC devices.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Sustained exploitation could lead to kernel memory exhaustion, causing system instability, crashes, or denial of service.
Likely Case
Gradual memory leak that may cause performance degradation or system instability over extended periods.
If Mitigated
Minimal impact with proper monitoring and memory management controls in place.
🎯 Exploit Status
Exploitation requires triggering the specific failure condition in dev_set_name() during RTC device allocation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in stable kernel commits: 0bcfc8fd3e596994f527b46730579428b3a4fa5f, 59457a0f079eae19aaf322b3cc1c8ba66f55c5f3, 60da73808298ff2cfa9f165d55eb3d7aa7078601
Vendor Advisory: https://git.kernel.org/stable/c/0bcfc8fd3e596994f527b46730579428b3a4fa5f
Restart Required: Yes
Instructions:
1. Update Linux kernel to a version containing the fix. 2. Check with your distribution for security updates. 3. Reboot the system after kernel update.
🔧 Temporary Workarounds
Disable vulnerable RTC modules
linuxPrevent loading of RTC drivers that might trigger the vulnerability
echo 'blacklist rtc_rx4581' >> /etc/modprobe.d/blacklist.conf
🧯 If You Can't Patch
- Monitor kernel memory usage and system stability
- Restrict local user access and kernel module loading capabilities
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if RTC devices are in use. Vulnerable if using unpatched kernel with RTC functionality.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits or is newer than the patched versions.📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- Memory allocation failures in dmesg
- System instability logs
Network Indicators:
- None - local vulnerability only
SIEM Query:
Search for kernel panic logs or memory allocation failures in system logs