CVE-2025-21870
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's Sound Open Firmware (SOF) subsystem could cause kernel crashes when processing malformed audio topology configurations. This affects systems using Intel audio DSPs with ALH copiers. Attackers with local access could trigger denial of service.
💻 Affected Systems
- Linux kernel with Sound Open Firmware (SOF) subsystem
📦 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash and denial of service, requiring physical or remote console access to reboot.
Likely Case
Audio subsystem malfunction or system crash when specific audio configurations are loaded, causing temporary denial of service.
If Mitigated
No impact if patched or if vulnerable audio configurations are not used.
🎯 Exploit Status
Requires local access and ability to load specific audio topology configurations. No known public exploits.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel versions containing the stable commits referenced in CVE description
Vendor Advisory: https://git.kernel.org/stable/c/6fd60136d256b3b948333ebdb3835f41a95ab7ef
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel package. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable SOF audio subsystem
linuxPrevent loading of SOF audio modules to avoid vulnerability
echo 'blacklist snd-sof-pci' | sudo tee /etc/modprobe.d/sof-blacklist.conf
sudo update-initramfs -u
sudo reboot
🧯 If You Can't Patch
- Restrict local access to prevent malicious users from loading audio configurations
- Monitor system logs for kernel panic events related to audio subsystem
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if SOF modules are loaded: 'uname -r' and 'lsmod | grep snd_sof'Check Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and check git commit history for the fix commits in kernel source📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- Audio subsystem crash logs
- NULL pointer dereference errors mentioning sof_ipc4
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("NULL pointer dereference" OR "kernel panic") AND ("sof" OR "audio" OR "ALH")