CVE-2025-38269
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's Btrfs filesystem could cause kernel panic or system crash when CONFIG_BUG is disabled. This affects Linux systems using Btrfs filesystem with specific kernel versions. The vulnerability requires local access to trigger.
💻 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 panic leading to system crash and denial of service, potentially causing data corruption in Btrfs filesystem operations.
Likely Case
System crash or kernel panic when the specific error condition occurs during Btrfs operations, resulting in temporary denial of service.
If Mitigated
Minimal impact as most systems have CONFIG_BUG enabled, which triggers a controlled BUG() call instead of invalid memory access.
🎯 Exploit Status
Requires local access and specific conditions to trigger the error path. Exploitation would likely cause denial of service rather than privilege escalation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 3bf179e36da917c5d9bec71c714573ed1649b7c1, 58c50f45e1821a04d61b62514f9bd34afe67c622, or 8d9d32088e304e2bc444a3087cab0bbbd9951866
Vendor Advisory: https://git.kernel.org/stable/c/3bf179e36da917c5d9bec71c714573ed1649b7c1
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
Ensure CONFIG_BUG is enabled
linuxCompile kernel with CONFIG_BUG=y to ensure BUG() calls trigger properly instead of falling through to vulnerable code path
Check current config: cat /boot/config-$(uname -r) | grep CONFIG_BUG
Recompile kernel with CONFIG_BUG=y if rebuilding
🧯 If You Can't Patch
- Avoid using Btrfs filesystem or limit Btrfs operations on affected systems
- Implement strict access controls to limit local users who could trigger the vulnerability
🔍 How to Verify
Check if Vulnerable:
Check kernel version and verify if it contains the vulnerable code by examining kernel source or distribution security advisoriesCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated to include the fix commits, and check that CONFIG_BUG is enabled in kernel configuration📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- Btrfs error messages related to extent operations
- System crash/reboot events
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("BUG" OR "panic" OR "Oops") AND ("btrfs" OR "extent_io_tree")