CVE-2021-47642
📋 TL;DR
This CVE describes a buffer overflow vulnerability in the NVIDIA framebuffer driver (nvidiafb) in the Linux kernel. The vulnerability allows an attacker with local access to potentially execute arbitrary code or cause a denial of service by exploiting improper string copying. Systems running affected Linux kernel versions with NVIDIA framebuffer support enabled are at risk.
💻 Affected Systems
- Linux kernel with NVIDIA framebuffer driver (nvidiafb)
📦 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 →⚠️ Risk & Real-World Impact
Worst Case
Local privilege escalation to root, allowing complete system compromise and potential lateral movement within the environment.
Likely Case
Kernel panic leading to denial of service, requiring system reboot to restore functionality.
If Mitigated
Minimal impact if proper access controls prevent local attackers from accessing the vulnerable interface.
🎯 Exploit Status
Requires local access and knowledge of how to trigger the vulnerable code path. No known public exploits.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel versions containing the fix commits (e.g., 055cdd2e7b992921424d4daaa285ced787fb205f and related)
Vendor Advisory: https://git.kernel.org/stable/c/055cdd2e7b992921424d4daaa285ced787fb205f
Restart Required: No
Instructions:
1. Update Linux kernel to a version containing the fix. 2. For distributions: Use package manager (apt/yum/dnf) to install latest kernel updates. 3. Reboot to load new kernel if not using kexec or livepatch.
🔧 Temporary Workarounds
Disable NVIDIA framebuffer driver
allPrevent loading of the vulnerable nvidiafb module
echo 'blacklist nvidiafb' >> /etc/modprobe.d/blacklist.conf
rmmod nvidiafb
🧯 If You Can't Patch
- Restrict local access to prevent potential attackers from reaching the system
- Implement strict privilege separation to limit damage if exploited
🔍 How to Verify
Check if Vulnerable:
Check if nvidiafb module is loaded: lsmod | grep nvidiafb AND check kernel version against patched versionsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated beyond fix commits and nvidiafb module uses strscpy instead of strcpy in nvidia_setup_i2c_bus function📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- System crashes/reboots without clear cause
Network Indicators:
- None - local vulnerability only
SIEM Query:
Search for kernel panic events or unexpected system reboots in system logs🔗 References
- https://git.kernel.org/stable/c/055cdd2e7b992921424d4daaa285ced787fb205f
- https://git.kernel.org/stable/c/08dff482012758935c185532b1ad7d584785a86e
- https://git.kernel.org/stable/c/37a1a2e6eeeb101285cd34e12e48a881524701aa
- https://git.kernel.org/stable/c/41baa86b6c802cdc6ab8ff2d46c083c9be93de81
- https://git.kernel.org/stable/c/47e5533adf118afaf06d25a3e2aaaab89371b1c5
- https://git.kernel.org/stable/c/580e5d3815474b8349250c25c16416585a72c7fe
- https://git.kernel.org/stable/c/6a5226e544ac043bb2d8dc1bfe8920d02282f7cd
- https://git.kernel.org/stable/c/72dd5c46a152136712a55bf026a9aa8c1b12b60d
- https://git.kernel.org/stable/c/9ff2f7294ab0f011cd4d1b7dcd9a07d8fdf72834
