CVE-2021-47350
📋 TL;DR
This vulnerability in the Linux kernel's powerpc architecture causes a lockup when the kernel attempts to execute code from a userspace address. It affects systems running Linux with powerpc processors when specific kernel versions are used. The issue occurs because the kernel incorrectly handles execution faults, leading to an infinite loop of minor faults.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel lockup leading to denial of service, requiring system reboot to recover.
Likely Case
System instability or crash when specific kernel operations trigger the execution fault condition.
If Mitigated
No impact if patched or if the specific triggering conditions are avoided.
🎯 Exploit Status
Exploitation requires triggering specific kernel execution fault conditions, which may be difficult to achieve reliably.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions with fixes from commits listed in references
Vendor Advisory: https://git.kernel.org/stable/c/500f81cec9f1bfa5210aa9dd5ba9a06e22f62a35
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing fix commits. 2. Reboot system. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Avoid triggering execution faults
linuxPrevent conditions that could trigger kernel execution faults from userspace addresses
🧯 If You Can't Patch
- Monitor system for lockups and have reboot procedures ready
- Restrict access to systems to prevent malicious triggering of the condition
🔍 How to Verify
Check if Vulnerable:
Check kernel version and configuration. Vulnerable if running affected powerpc kernel versions between problematic commits.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits: 500f81cec9f1bfa5210aa9dd5ba9a06e22f62a35 or later fixes📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- System lockup events
- Watchdog timeouts
Network Indicators:
- None - local vulnerability only
SIEM Query:
Search for kernel panic or system lockup events in system logs🔗 References
- https://git.kernel.org/stable/c/500f81cec9f1bfa5210aa9dd5ba9a06e22f62a35
- https://git.kernel.org/stable/c/8a96ec5ebf96ad8e2ba7b1b34103a0be5140fc70
- https://git.kernel.org/stable/c/a82471a14aad90f79d1608d2bcbb019f0ffb53f0
- https://git.kernel.org/stable/c/cd5d5e602f502895e47e18cd46804d6d7014e65c
- https://git.kernel.org/stable/c/d2e52d4664097a6c1f591d869ec594bd7a0d4925
- https://git.kernel.org/stable/c/500f81cec9f1bfa5210aa9dd5ba9a06e22f62a35
- https://git.kernel.org/stable/c/8a96ec5ebf96ad8e2ba7b1b34103a0be5140fc70
- https://git.kernel.org/stable/c/a82471a14aad90f79d1608d2bcbb019f0ffb53f0
- https://git.kernel.org/stable/c/cd5d5e602f502895e47e18cd46804d6d7014e65c
- https://git.kernel.org/stable/c/d2e52d4664097a6c1f591d869ec594bd7a0d4925
