CVE-2025-38632
📋 TL;DR
A race condition in the Linux kernel's pinmux subsystem can cause a NULL pointer dereference when multiple processes concurrently access the same GPIO pin. This affects Linux systems using GPIO pin multiplexing, potentially leading to kernel crashes or system instability.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash and denial of service, requiring physical or remote reboot.
Likely Case
System instability, occasional kernel crashes, or unexpected behavior in GPIO-dependent applications.
If Mitigated
Minor performance impact from proper locking, with stable GPIO operations.
🎯 Exploit Status
Requires local access and ability to trigger concurrent GPIO operations. Timing-dependent race condition makes exploitation challenging but possible.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 0b075c011032f88d1cfde3b45d6dcf08b44140eb, 22b585cbd67d14df3b91529d1b990661c300faa9, 9b2a3e7189028aa7c4d53a84364f2ea9fb209787, 9ea3f6b9a67be3476e331ce51cac316c2614a564, b7bd6e3971eb7f0e34d2fdce1b18b08094e0c804
Vendor Advisory: https://git.kernel.org/stable/c/0b075c011032f88d1cfde3b45d6dcf08b44140eb
Restart Required: Yes
Instructions:
1. Update to a kernel version containing the fix commits. 2. Check your distribution's security advisories for backported patches. 3. Reboot the system after kernel update.
🔧 Temporary Workarounds
Limit GPIO access
LinuxRestrict which users or processes can access GPIO functionality to reduce concurrent access scenarios.
chmod 600 /dev/gpio*
setfacl -m u:username:rw- /dev/gpio*
🧯 If You Can't Patch
- Implement strict access controls on GPIO devices
- Monitor system logs for kernel panic or NULL pointer dereference events
🔍 How to Verify
Check if Vulnerable:
Check kernel version and verify if it contains the vulnerable pinmux code. Run: uname -r and compare with affected versions.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits. Check /proc/version or use: grep -i 'pinmux' /proc/kallsyms | grep -i 'fix'📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- NULL pointer dereference in kernel logs
- GPIO-related error messages in dmesg
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("NULL pointer" OR "panic" OR "oops") AND "pinmux"🔗 References
- https://git.kernel.org/stable/c/0b075c011032f88d1cfde3b45d6dcf08b44140eb
- https://git.kernel.org/stable/c/22b585cbd67d14df3b91529d1b990661c300faa9
- https://git.kernel.org/stable/c/9b2a3e7189028aa7c4d53a84364f2ea9fb209787
- https://git.kernel.org/stable/c/9ea3f6b9a67be3476e331ce51cac316c2614a564
- https://git.kernel.org/stable/c/b7bd6e3971eb7f0e34d2fdce1b18b08094e0c804
