CVE-2025-38594
📋 TL;DR
A use-after-free vulnerability in the Linux kernel's Intel IOMMU driver allows attackers with local access to potentially trigger kernel panics or achieve privilege escalation. This affects systems using Intel processors with IOMMU/SVM (Shared Virtual Memory) enabled and running vulnerable kernel versions. The vulnerability occurs during SVA (Shared Virtual Address) unbind operations when pending I/O page faults exist.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to denial of service, or potential privilege escalation allowing full system compromise.
Likely Case
System crashes or instability when devices with pending I/O page faults are detached from domains.
If Mitigated
No impact if IOMMU/SVM is disabled or systems are patched.
🎯 Exploit Status
Exploitation requires local access and knowledge of IOMMU/SVA operations. The vulnerability was discovered through code review and debugging.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits c68332b7ee893292bba6e87d31ef2080c066c65d and f0b9d31c6edd50a6207489cd1bd4ddac814b9cd2
Vendor Advisory: https://git.kernel.org/stable/c/c68332b7ee893292bba6e87d31ef2080c066c65d
Restart Required: Yes
Instructions:
1. Update to a kernel version containing the fix commits. 2. Check with your Linux distribution for security updates. 3. Reboot the system after kernel update.
🔧 Temporary Workarounds
Disable IOMMU/SVM features
linuxDisable Intel IOMMU or Shared Virtual Memory features if not required
Add 'intel_iommu=off' or 'iommu=off' to kernel boot parameters
🧯 If You Can't Patch
- Disable IOMMU/SVM features via kernel boot parameters
- Restrict local user access to systems with IOMMU/SVM enabled
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if IOMMU/SVM is enabled: 'cat /proc/cmdline | grep -i iommu' and 'dmesg | grep -i iommu'Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits or check with distribution's security advisory📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages mentioning 'refcount_t: underflow' or 'use-after-free'
- IOMMU-related error messages in dmesg
- System crashes during device detachment operations
Network Indicators:
- None - local vulnerability only
SIEM Query:
Search for kernel panic events or refcount underflow warnings in system logs