CVE-2021-47081
📋 TL;DR
This is a use-after-free vulnerability in the Linux kernel's Habana Labs Gaudi AI accelerator driver. It could allow local attackers to cause kernel memory corruption, potentially leading to privilege escalation or denial of service. Systems using Habana Gaudi AI accelerators with vulnerable kernel versions are affected.
💻 Affected Systems
- Linux kernel with Habana Labs Gaudi driver
📦 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
Local privilege escalation to root, kernel panic causing system crash, or arbitrary code execution in kernel context.
Likely Case
Kernel crash leading to denial of service, system instability, or memory corruption.
If Mitigated
Limited impact if proper access controls prevent local users from accessing the vulnerable driver interface.
🎯 Exploit Status
Requires local access and ability to interact with the Gaudi driver interface. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel with commits 115726c5d312b462c9d9931ea42becdfa838a076 and b49f5af30b0e4064fbd91e83823a4bfcb2c7a3e7
Vendor Advisory: https://git.kernel.org/stable/c/115726c5d312b462c9d9931ea42becdfa838a076
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Rebuild kernel if compiling from source. 3. Reboot system to load patched kernel.
🔧 Temporary Workarounds
Disable Gaudi driver module
linuxPrevent loading of the vulnerable driver if Gaudi accelerator is not required
echo 'blacklist habanalabs' >> /etc/modprobe.d/blacklist.conf
rmmod habanalabs
Restrict driver access
linuxLimit which users can access the Gaudi device files
chmod 600 /dev/habanalabs/*
setfacl -m u:root:rw /dev/habanalabs/*
🧯 If You Can't Patch
- Restrict local user access to systems with Gaudi accelerators
- Implement strict privilege separation and limit sudo/root access
🔍 How to Verify
Check if Vulnerable:
Check if habanalabs kernel module is loaded: lsmod | grep habanalabs. Check kernel version: uname -r and compare with patched versions.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits: git log --oneline | grep -E '115726c5d312|b49f5af30b0e'📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- System crashes/panics
- dmesg errors related to habanalabs or memory corruption
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("habanalabs" OR "use-after-free" OR "kernel panic")