CVE-2024-46736
📋 TL;DR
This CVE describes a double-free vulnerability in the Linux kernel's SMB client implementation. When the smb2_rename_path() function encounters an error condition, it can incorrectly release the same file handle twice, potentially leading to memory corruption. This affects any Linux system using the kernel's built-in SMB client functionality.
💻 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, denial of service, or potential privilege escalation if memory corruption can be weaponized.
Likely Case
System instability, kernel crashes, or denial of service affecting SMB file operations.
If Mitigated
Minimal impact if systems are patched or don't use the vulnerable SMB client functionality.
🎯 Exploit Status
Exploitation requires attacker to control an SMB server that the victim connects to, or ability to manipulate SMB responses.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 1a46c7f6546b73cbf36f5a618a1a6bbb45391eb3, 3523a3df03c6f04f7ea9c2e7050102657e331a4f, or b27ea9c96efd2c252a981fb00d0f001b86c90f3e
Vendor Advisory: https://git.kernel.org/stable/c/1a46c7f6546b73cbf36f5a618a1a6bbb45391eb3
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable SMB client modules
linuxPrevent loading of vulnerable SMB client kernel modules
echo 'blacklist cifs' >> /etc/modprobe.d/blacklist.conf
echo 'blacklist smb2' >> /etc/modprobe.d/blacklist.conf
update-initramfs -u
reboot
Restrict SMB client usage
allPrevent systems from connecting to untrusted SMB servers
🧯 If You Can't Patch
- Restrict SMB client connections to trusted internal servers only
- Implement network segmentation to isolate systems using SMB client functionality
🔍 How to Verify
Check if Vulnerable:
Check kernel version and verify if it contains the vulnerable smb2_rename_path() code. Use 'uname -r' and compare with distribution security advisories.Check Version:
uname -rVerify Fix Applied:
Verify kernel version after update contains the fix commits. Check with 'uname -r' and confirm with distribution's security patch notes.📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- OOM killer messages related to SMB
- System crashes during SMB file operations
Network Indicators:
- Unexpected SMB connections to untrusted servers
- SMB protocol anomalies
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "BUG") AND ("cifs" OR "smb")