CVE-2024-44981
📋 TL;DR
This CVE-2024-44981 is an integer overflow vulnerability in the Linux kernel's workqueue subsystem that can cause kernel panic during boot. It affects Linux systems running vulnerable kernel versions, particularly when booting in virtualized environments like Android VMs. The vulnerability is triggered during delayed work cancellation 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 →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 and denial of service, potentially causing data loss or corruption if the system is in the middle of critical operations.
Likely Case
System crash during boot or when specific workqueue operations are performed, resulting in denial of service.
If Mitigated
No impact if patched; systems with proper kernel hardening may detect and log the overflow without crashing.
🎯 Exploit Status
The vulnerability was discovered through UBSAN (Undefined Behavior Sanitizer) during boot. Exploitation would require local access and ability to trigger the vulnerable code path.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees via commits 38f7e14519d39cf524ddc02d4caee9b337dad703 and 90a6a844b2d9927d192758438a4ada33d8cd9de5
Vendor Advisory: https://git.kernel.org/stable/c/38f7e14519d39cf524ddc02d4caee9b337dad703
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix. 2. Check with your distribution for kernel security updates. 3. Rebuild kernel if using custom kernel. 4. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable UBSAN detection
linuxDisable Undefined Behavior Sanitizer to prevent detection of the overflow, though this doesn't fix the underlying issue.
Add 'ubsan=0' to kernel boot parameters
🧯 If You Can't Patch
- Restrict local user access to minimize chance of triggering the vulnerability
- Monitor system logs for kernel panic events and have recovery procedures ready
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions. The vulnerability is in shift_and_mask() function in workqueue.cCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated to include the fix commits. Check that '1U' is used instead of signed constant in shift_and_mask() function.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- UBSAN: integer subtraction overflow errors
- Call trace showing cancel_delayed_work+0x34/0x44
Network Indicators:
- None - this is a local kernel vulnerability
SIEM Query:
Search for kernel logs containing 'UBSAN: integer subtraction overflow' or 'Kernel panic' with workqueue/cancel_delayed_work references