CVE-2025-38614
📋 TL;DR
This CVE addresses a semi-unbounded recursion vulnerability in the Linux kernel's eventpoll (epoll) subsystem. Attackers could potentially cause kernel crashes or denial-of-service by creating deeply nested epoll graphs. This affects all Linux systems using epoll for I/O event notification.
💻 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 →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 affecting multiple services on the host
Likely Case
Local denial-of-service through kernel resource exhaustion, causing system instability or service disruption
If Mitigated
Limited impact with proper privilege separation and resource limits in place
🎯 Exploit Status
Requires local access and ability to create epoll file descriptors; exploit would need to craft specific epoll graph structures
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing fixes from the referenced commits
Vendor Advisory: https://git.kernel.org/stable/c/1b13b033062824495554e836a1ff5f85ccf6b039
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 after reboot
🔧 Temporary Workarounds
Limit epoll usage
allRestrict applications from creating deeply nested epoll structures through application-level controls
🧯 If You Can't Patch
- Implement strict privilege separation to limit which users/processes can create epoll instances
- Monitor system for unusual epoll usage patterns and resource exhaustion
🔍 How to Verify
Check if Vulnerable:
Check kernel version against distribution security advisories; vulnerable if using unpatched kernel with epoll supportCheck Version:
uname -rVerify Fix Applied:
Verify kernel version matches patched version from vendor advisory; test epoll functionality remains working📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- System crash dumps
- Resource exhaustion warnings
Network Indicators:
- Service disruptions on affected hosts
SIEM Query:
Search for kernel panic events or system crash reports on Linux hosts🔗 References
- https://git.kernel.org/stable/c/1b13b033062824495554e836a1ff5f85ccf6b039
- https://git.kernel.org/stable/c/2a0c0c974bea9619c6f41794775ae4b97530e0e6
- https://git.kernel.org/stable/c/3542c90797bc3ab83ebab54b737d751cf3682036
- https://git.kernel.org/stable/c/71379495ab70eaba19224bd71b5b9b399eb85e04
- https://git.kernel.org/stable/c/7a2125962c42d5336ca0495a9ce4cb38a63e9161
- https://git.kernel.org/stable/c/ea5f97dbdcb1651581a22bd10afd2f0dd9dc11d6
- https://git.kernel.org/stable/c/f2e467a48287c868818085aa35389a224d226732
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
