CVE-2025-39905
📋 TL;DR
A race condition vulnerability in the Linux kernel's phylink networking subsystem allows concurrent modification of the phylink structure (pl->phydev) during network interface resolution. This can lead to use-after-free conditions, memory corruption, or kernel crashes. Affects Linux systems with network interfaces using the phylink subsystem.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash, potential denial of service, or privilege escalation if combined with other vulnerabilities.
Likely Case
System instability, network interface failures, or kernel crashes when network interfaces are being brought up/down concurrently.
If Mitigated
Minimal impact with proper kernel locking mechanisms and updated kernel versions.
🎯 Exploit Status
Exploitation requires local access or ability to trigger network interface state changes. Race conditions are difficult to exploit reliably.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees (commits 0ba5b2f2c381dbec9ed9e4ab3ae5d3e667de0dc3 and 56fe63b05ec84ae6674269d78397cec43a7a295a)
Vendor Advisory: https://git.kernel.org/stable/c/0ba5b2f2c381dbec9ed9e4ab3ae5d3e667de0dc3
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 matches patched release.
🔧 Temporary Workarounds
Avoid concurrent network interface operations
linuxMinimize simultaneous network interface bring-up/down operations that could trigger the race condition
🧯 If You Can't Patch
- Restrict network interface management to privileged users only
- Monitor system logs for kernel panics or network subsystem errors
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions from kernel.org stable treesCheck Version:
uname -rVerify Fix Applied:
Verify kernel version after update matches patched release and monitor for network stability📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- Network subsystem errors in dmesg
- Unexpected network interface failures
Network Indicators:
- Sudden loss of network connectivity
- Interface flapping
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "BUG") AND ("phylink" OR "phydev")