CVE-2024-26973
📋 TL;DR
This vulnerability in the Linux kernel's FAT filesystem driver leaks uninitialized memory when generating file handles without parent directories. It affects systems using the FAT filesystem with nostale filehandles enabled, potentially exposing kernel memory contents to userspace applications. The risk is limited to information disclosure rather than code execution.
💻 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 →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
An attacker could obtain sensitive kernel memory contents including cryptographic keys, process information, or other privileged data that could facilitate further attacks.
Likely Case
Limited information disclosure of random kernel memory contents, potentially revealing system state information but unlikely to directly enable privilege escalation.
If Mitigated
With proper access controls and filesystem isolation, impact is minimal as only users with filesystem access can trigger the vulnerability.
🎯 Exploit Status
Exploitation requires local access and ability to interact with FAT filesystem; no authentication bypass needed beyond filesystem permissions.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions with commits: 03a7e3f2ba3ca25f1da1d3898709a08db14c1abb, 74f852654b8b7866f15323685f1e178d3386c688, 9840d1897e28f8733cc1e38f97e044f987dc0a63, a276c595c3a629170b0f052a3724f755d7c6adc6, b7fb63e807c6dadf7ecc1d43448c4f1711d7eeee
Vendor Advisory: https://git.kernel.org/stable/c/03a7e3f2ba3ca25f1da1d3898709a08db14c1abb
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
Disable FAT filesystem mounting
linuxPrevent mounting of FAT filesystems to avoid exposure
# Remove FAT module: rmmod fat
# Blacklist FAT module: echo 'blacklist fat' > /etc/modprobe.d/blacklist-fat.conf
Use alternative filesystems
linuxReplace FAT with ext4 or other filesystems for storage
# Convert FAT partition: mkfs.ext4 /dev/sdX1
🧯 If You Can't Patch
- Restrict access to FAT filesystems to trusted users only
- Implement strict filesystem permissions and monitor for unusual file operations
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if FAT filesystem is in use: lsmod | grep fat && uname -rCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and check for presence of fix commits in kernel source📡 Detection & Monitoring
Log Indicators:
- Unusual file handle operations on FAT filesystems
- Kernel warnings about uninitialized memory
Network Indicators:
- None - local vulnerability only
SIEM Query:
process.name="kernel" AND (event.category="memory" OR event.category="filesystem") AND filesystem.type="fat"🔗 References
- https://git.kernel.org/stable/c/03a7e3f2ba3ca25f1da1d3898709a08db14c1abb
- https://git.kernel.org/stable/c/74f852654b8b7866f15323685f1e178d3386c688
- https://git.kernel.org/stable/c/9840d1897e28f8733cc1e38f97e044f987dc0a63
- https://git.kernel.org/stable/c/a276c595c3a629170b0f052a3724f755d7c6adc6
- https://git.kernel.org/stable/c/b7fb63e807c6dadf7ecc1d43448c4f1711d7eeee
- https://git.kernel.org/stable/c/c8cc05de8e6b5612b6e9f92c385c1a064b0db375
- https://git.kernel.org/stable/c/cdd33d54e789d229d6d5007cbf3f53965ca1a5c6
- https://git.kernel.org/stable/c/f52d7663a10a1266a2d3871a6dd8fd111edc549f
- https://git.kernel.org/stable/c/fde2497d2bc3a063d8af88b258dbadc86bd7b57c
- https://git.kernel.org/stable/c/03a7e3f2ba3ca25f1da1d3898709a08db14c1abb
- https://git.kernel.org/stable/c/74f852654b8b7866f15323685f1e178d3386c688
- https://git.kernel.org/stable/c/9840d1897e28f8733cc1e38f97e044f987dc0a63
- https://git.kernel.org/stable/c/a276c595c3a629170b0f052a3724f755d7c6adc6
- https://git.kernel.org/stable/c/b7fb63e807c6dadf7ecc1d43448c4f1711d7eeee
- https://git.kernel.org/stable/c/c8cc05de8e6b5612b6e9f92c385c1a064b0db375
- https://git.kernel.org/stable/c/cdd33d54e789d229d6d5007cbf3f53965ca1a5c6
- https://git.kernel.org/stable/c/f52d7663a10a1266a2d3871a6dd8fd111edc549f
- https://git.kernel.org/stable/c/fde2497d2bc3a063d8af88b258dbadc86bd7b57c
- https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html
- https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html
