CVE-2022-49288
📋 TL;DR
A race condition vulnerability in the Linux kernel's ALSA PCM subsystem allows concurrent writes to proc files controlling buffer preallocation, potentially leading to use-after-free or other memory corruption issues. This affects Linux systems with ALSA sound subsystem enabled, particularly those allowing users to modify PCM buffer settings via /proc filesystem. Attackers with local access could exploit this to crash the system or potentially escalate privileges.
💻 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
Local privilege escalation to kernel-level access, system crash, or arbitrary code execution in kernel context leading to complete system compromise.
Likely Case
Kernel panic or system crash causing denial of service, potentially allowing limited information disclosure or privilege escalation depending on exploitation success.
If Mitigated
System remains stable with no impact if proper access controls prevent unauthorized users from writing to ALSA proc files.
🎯 Exploit Status
Exploitation requires local access and race condition timing, making it moderately complex. No public exploits known as of knowledge cutoff.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel with commits 37b12c16beb6f6c1c3c678c1aacbc46525c250f7, 51fce708ab8986a9879ee5da946a2cc120f1036d, 5ed8f8e3c4e59d0396b9ccf2e639711e24295bb6, 69534c48ba8ce552ce383b3dfdb271ffe51820c3, or a21d2f323b5a978dedf9ff1d50f101f85e39b3f2
Vendor Advisory: https://git.kernel.org/stable/c/37b12c16beb6f6c1c3c678c1aacbc46525c250f7
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution's repositories. 2. For custom kernels, apply the relevant commit from kernel.org. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Restrict proc filesystem access
LinuxLimit write access to ALSA proc files to prevent unauthorized modifications
chmod 644 /proc/asound/*/pcm*/sub*/prealloc
chmod 644 /proc/asound/*/pcm*/sub*/prealloc_max
🧯 If You Can't Patch
- Implement strict access controls on /proc/asound directory to prevent unauthorized writes
- Monitor system logs for unusual ALSA/proc file access patterns and investigate suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if ALSA proc files exist: ls -la /proc/asound/*/pcm*/sub*/prealloc* 2>/dev/nullCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits or is newer than vulnerable versions. Check with: uname -r and compare with distribution's patched versions.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- ALSA subsystem errors in dmesg
- Unusual access patterns to /proc/asound files in audit logs
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "ALSA error") OR source="audit" AND path="/proc/asound/*" AND action="write"🔗 References
- https://git.kernel.org/stable/c/37b12c16beb6f6c1c3c678c1aacbc46525c250f7
- https://git.kernel.org/stable/c/51fce708ab8986a9879ee5da946a2cc120f1036d
- https://git.kernel.org/stable/c/5ed8f8e3c4e59d0396b9ccf2e639711e24295bb6
- https://git.kernel.org/stable/c/69534c48ba8ce552ce383b3dfdb271ffe51820c3
- https://git.kernel.org/stable/c/a21d2f323b5a978dedf9ff1d50f101f85e39b3f2
- https://git.kernel.org/stable/c/b560d670c87d7d40b3cf6949246fa4c7aa65a00a
- https://git.kernel.org/stable/c/e14dca613e0a6ddc2bf6e360f16936a9f865205b
- https://git.kernel.org/stable/c/e7786c445bb67a9a6e64f66ebd6b7215b153ff7d
