CVE-2025-38306
📋 TL;DR
A race condition vulnerability in the Linux kernel's filesystem handle code could allow local attackers to cause a kernel oops (crash) or potentially escalate privileges. This affects Linux systems where unprivileged users can access filesystem operations. The vulnerability exists in the may_decode_fh() function which calls has_locked_children() without proper locking.
💻 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
Local privilege escalation to root or kernel panic leading to denial of service
Likely Case
Kernel oops or system crash causing denial of service
If Mitigated
Minimal impact with proper access controls and SELinux/AppArmor restrictions
🎯 Exploit Status
Exploitation requires local access and knowledge of race condition timing. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel commits: 1f282cdc1d219c4a557f7009e81bc792820d9d9a, 287c7d34eedd37af1272dfb3b6e8656f4f026424, 6482c3dccbfb8d20e2856ce67c75856859930b3f
Vendor Advisory: https://git.kernel.org/stable/c/1f282cdc1d219c4a557f7009e81bc792820d9d9a
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
Restrict local user access
linuxLimit local user accounts and implement strict access controls
Enable SELinux/AppArmor
linuxUse mandatory access controls to restrict filesystem operations
setenforce 1
systemctl enable apparmor
🧯 If You Can't Patch
- Implement strict user access controls and limit local accounts
- Use containerization to isolate processes and limit kernel exposure
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions from kernel git repositoryCheck Version:
uname -rVerify Fix Applied:
Verify kernel version matches patched version and check for presence of __has_locked_children() function in kernel source📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages in /var/log/kern.log or dmesg
- System crash/panic logs
Network Indicators:
- None - local exploit only
SIEM Query:
source="kernel" AND ("oops" OR "panic" OR "BUG") AND process="may_decode_fh"