CVE-2025-39697
📋 TL;DR
This CVE describes a race condition vulnerability in the Linux kernel's NFS client implementation. It allows concurrent operations to interfere with write request handling, potentially causing data corruption or system instability. Systems using NFS mounts with affected Linux kernel versions are vulnerable.
💻 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
Data corruption in NFS-mounted filesystems, system crashes, or denial of service affecting NFS operations.
Likely Case
Intermittent data corruption or application errors when multiple processes access the same NFS-mounted files concurrently.
If Mitigated
Minor performance impact or rare edge-case issues in NFS operations.
🎯 Exploit Status
Exploitation requires race condition timing and NFS usage. Likely requires local access or ability to trigger specific NFS operations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 0ff42a32784e0f2cb46a46da8e9f473538c13e1b, 181feb41f0b268e6288bf9a7b984624d7fe2031d, 202a3432d21ac060629a760fff3b0a39859da3ea, 76d2e3890fb169168c73f2e4f8375c7cc24a765e, 92278ae36935a54e65fef9f8ea8efe7e80481ace
Vendor Advisory: https://git.kernel.org/stable/c/0ff42a32784e0f2cb46a46da8e9f473538c13e1b
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 NFS client usage
allAvoid using NFS mounts on affected systems
umount /path/to/nfs/mount
comment out NFS entries in /etc/fstab
🧯 If You Can't Patch
- Monitor NFS operations for corruption or errors
- Implement strict access controls to limit concurrent NFS file access
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions from kernel git commitsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version after update matches patched version containing the fix commits📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- NFS client errors in system logs
- Filesystem corruption errors
Network Indicators:
- Unusual NFS protocol errors
- Increased NFS retransmissions
SIEM Query:
source="kernel" AND ("NFS" OR "nfs_inode_remove_request") AND (error OR panic OR oops)🔗 References
- https://git.kernel.org/stable/c/0ff42a32784e0f2cb46a46da8e9f473538c13e1b
- https://git.kernel.org/stable/c/181feb41f0b268e6288bf9a7b984624d7fe2031d
- https://git.kernel.org/stable/c/202a3432d21ac060629a760fff3b0a39859da3ea
- https://git.kernel.org/stable/c/76d2e3890fb169168c73f2e4f8375c7cc24a765e
- https://git.kernel.org/stable/c/92278ae36935a54e65fef9f8ea8efe7e80481ace
- https://git.kernel.org/stable/c/c32e3c71aaa1c1ba05da88605e2ddd493c58794f
- https://git.kernel.org/stable/c/f230d40147cc37eb3aef4d50e2e2c06ea73d9a77
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
