CVE-2025-38492
📋 TL;DR
A race condition in the Linux kernel's netfs subsystem can cause asynchronous cache write requests to hang indefinitely when using copy-to-cache operations. This affects systems using Ceph or other filesystems that leverage netfslib's asynchronous caching functionality, potentially leading to resource exhaustion and 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 →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
System becomes unresponsive due to hung kernel threads accumulating, potentially leading to denial of service requiring system reboot.
Likely Case
Intermittent file system operations fail or hang when using Ceph or similar distributed filesystems with caching enabled, causing application timeouts.
If Mitigated
Minor performance impact or occasional cache write failures that applications can handle gracefully.
🎯 Exploit Status
Exploitation requires specific timing conditions and filesystem configuration. More likely to occur as a reliability bug than be actively exploited.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel commits 110188a13c4853bd4c342e600ced4dfd26c3feb5 and 89635eae076cd8eaa5cb752f66538c9dc6c9fdc3
Vendor Advisory: https://git.kernel.org/stable/c/110188a13c4853bd4c342e600ced4dfd26c3feb5
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Check with your distribution for backported patches. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable asynchronous caching
linuxConfigure filesystem to use synchronous caching mode instead of asynchronous
Filesystem-specific configuration required (e.g., Ceph mount options)
🧯 If You Can't Patch
- Monitor system for hung processes related to filesystem operations
- Implement application-level retry logic for storage operations
🔍 How to Verify
Check if Vulnerable:
Check kernel version and verify if using Ceph or other netfslib-enabled filesystems with asynchronous cachingCheck Version:
uname -rVerify Fix Applied:
Verify kernel includes commits 110188a13c4853bd4c342e600ced4dfd26c3feb5 and 89635eae076cd8eaa5cb752f66538c9dc6c9fdc3📡 Detection & Monitoring
Log Indicators:
- Kernel messages about hung tasks
- Filesystem operation timeouts in application logs
- Ceph client connection issues
Network Indicators:
- Increased latency in storage operations
- Timeout errors from distributed storage clients
SIEM Query:
Search for: 'hung task' OR 'D state process' AND ('ceph' OR 'netfs' OR filesystem operations)