CVE-2025-37821
📋 TL;DR
A Linux kernel scheduling vulnerability in the EEVDF scheduler can cause kernel crashes when specific conditions trigger a sched_entity's slice value to be set to U64_MAX. This affects Linux systems using the affected kernel versions and can lead to denial of service. 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 →⚠️ 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 requiring reboot, causing temporary service interruption.
If Mitigated
No impact if patched; unpatched systems remain vulnerable to crashes under specific scheduling conditions.
🎯 Exploit Status
Exploitation requires specific scheduling conditions and local access; not trivial to trigger reliably.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in kernel commits: 50a665496881, 86b37810fa1e, bbce3de72be5
Vendor Advisory: https://git.kernel.org/stable/c/50a665496881262519f115f1bfe5822f30580eb0
Restart Required: Yes
Instructions:
1. Update to patched kernel version from your distribution vendor. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable EEVDF scheduler
linuxSwitch to alternative scheduler if available
Add 'sched=default' to kernel boot parameters in GRUB configuration
🧯 If You Can't Patch
- Monitor system logs for kernel panic or crash indicators
- Implement process isolation to limit scheduling interactions
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if EEVDF scheduler is active: uname -r and check /proc/sys/kernel/sched_schedulerCheck Version:
uname -rVerify Fix Applied:
Verify kernel version matches patched version and system remains stable under load📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- System crash/reboot logs
- Scheduler-related kernel oops
Network Indicators:
- Sudden service unavailability
- Connection drops
SIEM Query:
event_type:kernel_panic OR event_type:system_crash AND process:scheduler