CVE-2022-50512
📋 TL;DR
This CVE describes a memory leak vulnerability in the Linux kernel's ext4 filesystem fast commit feature. If exploited, it could lead to kernel memory exhaustion over time, potentially causing system instability or denial of service. This affects Linux systems using ext4 filesystem with fast commit enabled.
💻 Affected Systems
- Linux kernel
⚠️ Risk & Real-World Impact
Worst Case
Sustained exploitation could exhaust kernel memory, leading to system crashes, denial of service, or kernel panic requiring system reboot.
Likely Case
Gradual memory consumption leading to system performance degradation, potential application failures, or system instability requiring maintenance.
If Mitigated
Minimal impact with proper monitoring and memory limits; system remains functional but may require occasional maintenance.
🎯 Exploit Status
Exploitation requires ability to trigger specific filesystem operations that cause krealloc failures in the fast commit path. This is a reliability issue rather than a security bypass.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions with commits 2cfb769d60a2a57eb3566765428b6131cd16dcfe and related fixes
Vendor Advisory: https://git.kernel.org/stable/c/2cfb769d60a2a57eb3566765428b6131cd16dcfe
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify kernel version matches patched release.
🔧 Temporary Workarounds
Disable ext4 fast commit feature
linuxMount ext4 filesystems without fast_commit option to avoid triggering the vulnerable code path
mount -o remount,no-fast_commit /mount/point
Add 'no-fast_commit' to /etc/fstab mount options
🧯 If You Can't Patch
- Disable ext4 fast commit feature on all affected filesystems
- Implement kernel memory monitoring and alerting for unusual consumption patterns
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if ext4 filesystems are mounted with fast_commit: uname -r && mount | grep ext4Check Version:
uname -rVerify Fix Applied:
Verify kernel version is patched and check dmesg for any memory leak warnings related to ext4_fc_record_regions📡 Detection & Monitoring
Log Indicators:
- Kernel OOM (Out of Memory) messages in dmesg
- Increasing kernel memory usage in system monitoring
- ext4 filesystem error messages
Network Indicators:
- None - this is a local filesystem vulnerability
SIEM Query:
source="kernel" AND ("out of memory" OR "OOM" OR "ext4" AND "memory")🔗 References
- https://git.kernel.org/stable/c/2cfb769d60a2a57eb3566765428b6131cd16dcfe
- https://git.kernel.org/stable/c/417b0455a0b6d0f60a2930592731d1f8340e24be
- https://git.kernel.org/stable/c/518566e71ad86b7c2f1bf6d9caee9588bb7ac158
- https://git.kernel.org/stable/c/7069d105c1f15c442b68af43f7fde784f3126739
- https://git.kernel.org/stable/c/a4058b869e6c5e517c79e30532a350d0f3115c3e
