CVE-2025-38706
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's ASoC (Audio System on Chip) subsystem could cause kernel crashes when removing PCM runtime objects. This affects systems using ALSA topology with ignored links due to missing hardware components. 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 →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, potentially causing data loss or service disruption.
Likely Case
System crash or kernel panic when unloading specific audio topology modules, resulting in temporary denial of service.
If Mitigated
No impact if proper kernel hardening and privilege separation are in place, as it requires local access.
🎯 Exploit Status
Requires local access and specific conditions (ALSA topology with ignored links). Not trivial to exploit but reproducible with specific audio configurations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees (commits: 2d91cb261cac6d885954b8f5da28b5c176c18131, 2fce20decc6a83f16dd73744150c4e7ea6c97c21, 41f53afe53a57a7c50323f99424b598190acf192, 7ce0a7255ce97ed7c54afae83fdbce712a1f0c9e, 7f8fc03712194fd4e2df28af7f7f7a38205934ef)
Vendor Advisory: https://git.kernel.org/stable/c/2d91cb261cac6d885954b8f5da28b5c176c18131
Restart Required: No
Instructions:
1. Update to a patched kernel version from your distribution's repository. 2. Apply kernel patches from stable tree if compiling custom kernel. 3. Reboot is required for kernel updates to take effect.
🔧 Temporary Workarounds
Disable ALSA topology loading
LinuxPrevent loading of ALSA topology files that could trigger the vulnerability
echo 'blacklist snd-soc-topology' >> /etc/modprobe.d/blacklist.conf
update-initramfs -u
🧯 If You Can't Patch
- Restrict local user access to systems with vulnerable kernels
- Monitor for kernel panic events and investigate audio module unloading activities
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if ALSA topology modules are loaded: lsmod | grep snd_soc_topologyCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and check git commit hashes for the fix in kernel source📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- ALSA topology module unloading errors
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "NULL pointer dereference") AND "snd_soc"🔗 References
- https://git.kernel.org/stable/c/2d91cb261cac6d885954b8f5da28b5c176c18131
- https://git.kernel.org/stable/c/2fce20decc6a83f16dd73744150c4e7ea6c97c21
- https://git.kernel.org/stable/c/41f53afe53a57a7c50323f99424b598190acf192
- https://git.kernel.org/stable/c/7ce0a7255ce97ed7c54afae83fdbce712a1f0c9e
- https://git.kernel.org/stable/c/7f8fc03712194fd4e2df28af7f7f7a38205934ef
- https://git.kernel.org/stable/c/82ba7b8cf9f6e3bf392a9f08ba3d1c0b200ccb94
- https://git.kernel.org/stable/c/8b465bedc2b417fd27c1d1ab7122882b4b60b1a0
- https://git.kernel.org/stable/c/cecc65827ef3df9754e097582d89569139e6cd1e
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
