CVE-2025-37836
📋 TL;DR
This CVE describes a memory leak vulnerability in the Linux kernel's PCI subsystem. If device_register() fails during pci_register_host_bridge(), the kernel fails to release a reference, causing a memory leak. This affects all Linux systems using PCI host bridge functionality.
💻 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
Sustained exploitation could lead to kernel memory exhaustion, causing system instability, denial of service, or potential kernel crashes.
Likely Case
Memory leak gradually consumes kernel memory over time, potentially leading to system performance degradation or instability requiring reboots.
If Mitigated
With proper monitoring and memory limits, impact is limited to occasional memory pressure and potential performance issues.
🎯 Exploit Status
Exploitation requires local access and ability to trigger device_register() failures in PCI subsystem. Found during code review, not active exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 3297497ad2246eb9243849bfbbc57a0dea97d76e, 804443c1f27883926de94c849d91f5b7d7d696e9, 9707d0c932f41006a2701afc926b232b50e356b4, b783478e0c53ffb4f04f25fb4e21ef7f482b05df, bbba4c50a2d2a1d3f3bf31cc4b8280cb492bf2c7
Vendor Advisory: https://git.kernel.org/stable/c/3297497ad2246eb9243849bfbbc57a0dea97d76e
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Check distribution-specific security advisories. 3. Reboot system after kernel update. 4. Verify kernel version post-update.
🔧 Temporary Workarounds
Monitor kernel memory usage
linuxImplement monitoring for kernel memory consumption to detect potential memory leaks
watch -n 5 'cat /proc/meminfo | grep -E "Slab|KernelStack|PageTables|VmallocUsed"'
Restrict PCI device operations
linuxLimit non-privileged user access to PCI device operations if possible
chmod 600 /sys/bus/pci/devices/*/config
chmod 600 /sys/bus/pci/devices/*/resource*
🧯 If You Can't Patch
- Implement strict monitoring of kernel memory usage and system stability
- Restrict local user access and implement least privilege principles
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions. Vulnerable if using kernel before fixes were applied.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes one of the fix commits: uname -r and check git log for commit hashes📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- Out of memory errors in dmesg
- System instability logs
Network Indicators:
- None - this is a local kernel vulnerability
SIEM Query:
source="kernel" AND ("out of memory" OR "kernel panic" OR "slab error")🔗 References
- https://git.kernel.org/stable/c/3297497ad2246eb9243849bfbbc57a0dea97d76e
- https://git.kernel.org/stable/c/804443c1f27883926de94c849d91f5b7d7d696e9
- https://git.kernel.org/stable/c/9707d0c932f41006a2701afc926b232b50e356b4
- https://git.kernel.org/stable/c/b783478e0c53ffb4f04f25fb4e21ef7f482b05df
- https://git.kernel.org/stable/c/bbba4c50a2d2a1d3f3bf31cc4b8280cb492bf2c7
- https://git.kernel.org/stable/c/bd2a352a0d72575f1842d28c14c10089f0cfe1ae
- https://git.kernel.org/stable/c/f4db1b2c9ae3d013733c302ee70cac943b7070c0
- https://git.kernel.org/stable/c/f9208aec86226524ec1cb68a09ac70e974ea6536
- https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
- https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html
