CVE-2025-39783
📋 TL;DR
A use-after-free vulnerability in the Linux kernel's PCI endpoint subsystem allows local attackers to potentially crash the system or execute arbitrary code with kernel privileges. This affects systems using PCI endpoint function drivers with configfs attribute groups, primarily servers and embedded devices with specific hardware configurations.
💻 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
Kernel panic leading to system crash or arbitrary code execution with kernel privileges, potentially resulting in complete system compromise.
Likely Case
System crash or kernel panic when removing specific PCI endpoint drivers via rmmod, causing denial of service.
If Mitigated
Minor system instability during driver removal operations with proper kernel hardening and isolation.
🎯 Exploit Status
Exploitation requires local access and ability to load/unload kernel modules. The vulnerability triggers during driver removal operations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in kernel commits: 0758862386f114d9ab1e23181461bd1e2e9ec4c6, 409af8b9f7b4f23cd0464e71c6cd6fe13c076ae2, 6cf65505523224cab1449d726d2ce8180c2941ee, 80ea6e6904fb2ba4ccb5d909579988466ec65358, a302bd89db35d8b7e279de4d2b41c16c7f191069
Vendor Advisory: https://git.kernel.org/stable/c/0758862386f114d9ab1e23181461bd1e2e9ec4c6
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Reboot system to load new kernel. 3. Verify kernel version with 'uname -r'.
🔧 Temporary Workarounds
Restrict kernel module loading
linuxPrevent unauthorized users from loading/unloading kernel modules that could trigger the vulnerability
sysctl -w kernel.modules_disabled=1
echo 1 > /proc/sys/kernel/modules_disabled
Disable PCI endpoint functionality
linuxRemove or disable PCI endpoint drivers if not required
rmmod pci_epf_* drivers if present
blacklist pci_epf modules in /etc/modprobe.d/
🧯 If You Can't Patch
- Restrict access to systems using PCI endpoint functionality to trusted users only
- Implement strict module signing and loading policies to prevent unauthorized driver operations
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if PCI endpoint drivers are loaded: 'lsmod | grep pci_epf' and 'uname -r'Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits and test driver removal: 'modprobe -r [pci_epf_driver]' should not crash📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- KASAN warnings in dmesg
- System crashes during driver removal
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("KASAN" OR "use-after-free" OR "pci_epf")🔗 References
- https://git.kernel.org/stable/c/0758862386f114d9ab1e23181461bd1e2e9ec4c6
- https://git.kernel.org/stable/c/409af8b9f7b4f23cd0464e71c6cd6fe13c076ae2
- https://git.kernel.org/stable/c/6cf65505523224cab1449d726d2ce8180c2941ee
- https://git.kernel.org/stable/c/80ea6e6904fb2ba4ccb5d909579988466ec65358
- https://git.kernel.org/stable/c/a302bd89db35d8b7e279de4d2b41c16c7f191069
- https://git.kernel.org/stable/c/d5aecddc3452371d9da82cdbb0c715812524b54b
- https://git.kernel.org/stable/c/d79123d79a8154b4318529b7b2ff7e15806f480b
- https://git.kernel.org/stable/c/dc4ffbd571716ff3b171418fb03abe80e720a7b1
- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
