CVE-2021-47039
📋 TL;DR
This CVE describes an out-of-bounds read vulnerability in the Linux kernel's ataflop driver. An attacker could potentially read kernel memory beyond allocated bounds, which could lead to information disclosure or system crashes. This affects Linux systems using the ataflop driver for floppy disk 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel memory disclosure leading to information leakage, potential privilege escalation if combined with other vulnerabilities, or kernel panic causing system crash.
Likely Case
System instability or crash when accessing floppy disk devices with malformed input, potentially causing denial of service.
If Mitigated
Minimal impact as floppy disk usage is rare in modern systems and the vulnerability requires local access.
🎯 Exploit Status
Exploitation requires local access and ability to interact with floppy disk subsystem. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in stable kernel versions via commits: 07f86aa8f4fe077be1b018cc177eb8c6573e5671, 1ffec389a6431782a8a28805830b6fae9bf00af1, 2a3a8bbca28b899806844c00d49ed1b7ccb50957
Vendor Advisory: https://git.kernel.org/stable/c/07f86aa8f4fe077be1b018cc177eb8c6573e5671
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from official kernel.org or distribution repositories. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable ataflop module
linuxPrevent loading of the vulnerable ataflop driver if floppy disk support is not needed
echo 'blacklist ataflop' >> /etc/modprobe.d/blacklist.conf
rmmod ataflop
🧯 If You Can't Patch
- Disable floppy disk support in kernel configuration and remove ataflop module
- Restrict access to floppy disk devices using filesystem permissions or SELinux/AppArmor policies
🔍 How to Verify
Check if Vulnerable:
Check if ataflop module is loaded: lsmod | grep ataflop. If loaded and kernel version is unpatched, system is vulnerable.Check Version:
uname -rVerify Fix Applied:
Check kernel version against patched versions and verify ataflop module is either not loaded or from patched kernel.📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages related to ataflop driver
- System crashes when accessing floppy devices
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Search for kernel panic logs or ataflop-related error messages in system logs🔗 References
- https://git.kernel.org/stable/c/07f86aa8f4fe077be1b018cc177eb8c6573e5671
- https://git.kernel.org/stable/c/1ffec389a6431782a8a28805830b6fae9bf00af1
- https://git.kernel.org/stable/c/2a3a8bbca28b899806844c00d49ed1b7ccb50957
- https://git.kernel.org/stable/c/07f86aa8f4fe077be1b018cc177eb8c6573e5671
- https://git.kernel.org/stable/c/1ffec389a6431782a8a28805830b6fae9bf00af1
- https://git.kernel.org/stable/c/2a3a8bbca28b899806844c00d49ed1b7ccb50957
