CVE-2022-50496
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Linux kernel's dm-cache subsystem that occurs when dm_resume() and dm_destroy() operations happen concurrently. Attackers could potentially exploit this to crash the system or execute arbitrary code with kernel privileges. All Linux systems using dm-cache 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash or potential arbitrary code execution with kernel privileges, resulting in complete system compromise.
Likely Case
System crash or kernel panic causing denial of service, requiring system reboot to restore functionality.
If Mitigated
Minimal impact if proper kernel hardening and privilege separation are implemented, though system instability may still occur.
🎯 Exploit Status
Exploitation requires local access and knowledge of concurrent dm_resume/dm_destroy operations. Race condition exploitation can be challenging.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Multiple stable kernel versions with fixes available (see references in CVE)
Vendor Advisory: https://git.kernel.org/stable/c/034cbc8d3b47a56acd89453c29632a9c117de09d
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution's repositories. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable dm-cache
linuxRemove or disable dm-cache functionality if not required
dmsetup remove cache_target_name
modprobe -r dm-cache
🧯 If You Can't Patch
- Restrict local user access to prevent potential privilege escalation
- Implement strict process isolation and limit users who can perform device mapper operations
🔍 How to Verify
Check if Vulnerable:
Check if dm-cache module is loaded: lsmod | grep dm_cache. Check kernel version against patched versions.Check Version:
uname -rVerify Fix Applied:
Verify kernel version after update matches patched version. Check that dm-cache operations no longer cause crashes.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- OOPs messages related to dm_cache or device mapper
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Search for kernel panic events or OOPs messages containing 'dm_cache' or 'device-mapper'🔗 References
- https://git.kernel.org/stable/c/034cbc8d3b47a56acd89453c29632a9c117de09d
- https://git.kernel.org/stable/c/2b17026685a270b2beaf1cdd9857fcedd3505c7e
- https://git.kernel.org/stable/c/2f097dfac7579fd84ff98eb1d3acd41d53a485f3
- https://git.kernel.org/stable/c/4d20032dd90664de09f2902a7ea49ae2f7771746
- https://git.kernel.org/stable/c/6a3e412c2ab131c54945327a7676b006f000a209
- https://git.kernel.org/stable/c/6a459d8edbdbe7b24db42a5a9f21e6aa9e00c2aa
- https://git.kernel.org/stable/c/6ac4f36910764cb510bafc4c3768544f86ca48ca
- https://git.kernel.org/stable/c/993406104d2b28fe470126a062ad37a1e21e792e
- https://git.kernel.org/stable/c/d2a0b298ebf83ab6236f66788a3541e91ce75a70
