CVE-2023-52991
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's network stack can cause kernel panic when processing UDP packets with GRO/GSO fraglist chaining enabled. This affects Linux systems using UDP segmentation offload features. The vulnerability allows denial of service attacks by crashing the kernel.
💻 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
Kernel panic leading to complete system crash and denial of service, requiring physical or remote console access to reboot the system.
Likely Case
System crash or instability when processing malformed UDP packets, resulting in temporary service disruption until system reboot.
If Mitigated
No impact if UDP GRO/GSO fraglist chaining is disabled or the system is patched.
🎯 Exploit Status
Exploitation requires sending specially crafted UDP packets to trigger the NULL pointer dereference. No public exploit code is known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits: 046de74f9af92ae9ffce75fa22a1795223f4fb54, 6446369fb9f083ce032448c5047da08e298b22e6, 876e8ca8366735a604bac86ff7e2732fc9d85d2d, 888dad6f3e85e3b2f8389bd6478f181efc72534d
Vendor Advisory: https://git.kernel.org/stable/c/046de74f9af92ae9ffce75fa22a1795223f4fb54
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Check with your distribution vendor for specific patched kernel versions. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable UDP GRO/GSO fraglist chaining
linuxDisable the vulnerable UDP segmentation offload feature to prevent exploitation
ethtool -K <interface> gro disable
ethtool -K <interface> gso disable
🧯 If You Can't Patch
- Implement network filtering to block suspicious UDP traffic patterns
- Use firewalls to restrict UDP traffic to only necessary sources and services
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with affected commit range. Use: uname -r and check if between vulnerable commits.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes one of the fix commits. Check /proc/version or use: grep -q '046de74f9af92ae9ffce75fa22a1795223f4fb54\|6446369fb9f083ce032448c5047da08e298b22e6\|876e8ca8366735a604bac86ff7e2732fc9d85d2d\|888dad6f3e85e3b2f8389bd6478f181efc72534d' /proc/version_signature📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/messages or dmesg
- NULL pointer dereference errors mentioning skb_segment_list
- System crash/reboot logs
Network Indicators:
- Unusual UDP traffic patterns to network interfaces
- Sudden service disruptions on UDP-based services
SIEM Query:
source="kernel" AND ("NULL pointer dereference" OR "skb_segment_list" OR "kernel panic")