CVE-2022-49541
📋 TL;DR
A double-free vulnerability in the Linux kernel's CIFS filesystem driver could allow local attackers to crash the system or potentially execute arbitrary code. This affects systems using CIFS/SMB mounts and requires local access to trigger during mount failures. The vulnerability is in the kernel's handling of failed mount operations.
💻 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
Local privilege escalation leading to kernel compromise and full system control
Likely Case
Kernel panic or system crash causing denial of service
If Mitigated
No impact if proper access controls prevent local users from mounting CIFS shares
🎯 Exploit Status
Requires local access and ability to trigger CIFS mount failures. No known public exploits as of analysis.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 8378a51e3f8140f60901fb27208cc7a6e47047b5, 9a167fc440e5693c1cdd7f07071e05658bd9d89d, ce0008a0e410cdd95f0d8cd81b2902ec10a660c4, ee71f8f1cd3c8c4a251fd3e8abc89215ae3457cb
Vendor Advisory: https://bugzilla.redhat.com/show_bug.cgi?id=2088799
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 after reboot.
🔧 Temporary Workarounds
Restrict CIFS mount permissions
allLimit which users can mount CIFS shares to reduce attack surface
chmod 700 /bin/mount
chmod 700 /sbin/mount.cifs
Use sudoers to restrict mount commands
🧯 If You Can't Patch
- Restrict local user access to systems with CIFS mounts
- Disable CIFS/SMB mounting capabilities for non-privileged users
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with distribution's patched versions. Use: uname -rCheck Version:
uname -rVerify Fix Applied:
Verify kernel version after update matches patched version from vendor. Check if CIFS module loads without errors.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- CIFS mount failures in system logs
- Double-free warnings in kernel logs
Network Indicators:
- Unusual CIFS mount attempts from local users
SIEM Query:
source="kernel" AND ("double free" OR "CIFS" AND "mount" AND "failed")