CVE-2021-47044
📋 TL;DR
This CVE describes a shift-out-of-bounds vulnerability in the Linux kernel's scheduler load_balance() function. It could allow local attackers to cause undefined behavior, potentially leading to kernel crashes or other instability. This affects Linux systems running vulnerable kernel versions.
💻 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
Kernel panic or system crash leading to denial of service, potentially allowing privilege escalation if combined with other vulnerabilities.
Likely Case
System instability, kernel crashes, or denial of service on affected systems.
If Mitigated
Minimal impact with proper kernel hardening and isolation controls in place.
🎯 Exploit Status
Exploitation requires local access and specific conditions to trigger the shift-out-of-bounds. No public exploit code identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Multiple stable kernel versions with fixes: 2f3eab368e313dba35fc2f51ede778bf7b030b54, 39a2a6eb5c9b66ea7c8055026303b3aa681b49a5, 805cea93e66ca7deaaf6ad3b67224ce47c104c2f, 80862cbf76c2646f709a57c4517aefe0b094c774
Vendor Advisory: https://git.kernel.org/stable/c/2f3eab368e313dba35fc2f51ede778bf7b030b54
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
Kernel module restrictions
linuxRestrict kernel module loading to prevent potential exploitation vectors
echo 1 > /proc/sys/kernel/modules_disabled
🧯 If You Can't Patch
- Implement strict access controls to limit local user privileges
- Monitor system logs for kernel panic or crash events
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions from kernel git repositoryCheck Version:
uname -rVerify Fix Applied:
Verify kernel version matches or exceeds patched versions listed in fix references📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- System crash logs
- Unexpected system reboots
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "BUG")🔗 References
- https://git.kernel.org/stable/c/2f3eab368e313dba35fc2f51ede778bf7b030b54
- https://git.kernel.org/stable/c/39a2a6eb5c9b66ea7c8055026303b3aa681b49a5
- https://git.kernel.org/stable/c/805cea93e66ca7deaaf6ad3b67224ce47c104c2f
- https://git.kernel.org/stable/c/80862cbf76c2646f709a57c4517aefe0b094c774
- https://git.kernel.org/stable/c/2f3eab368e313dba35fc2f51ede778bf7b030b54
- https://git.kernel.org/stable/c/39a2a6eb5c9b66ea7c8055026303b3aa681b49a5
- https://git.kernel.org/stable/c/805cea93e66ca7deaaf6ad3b67224ce47c104c2f
- https://git.kernel.org/stable/c/80862cbf76c2646f709a57c4517aefe0b094c774
