Critical Vulnerability in Linux Kernel: vxlan_vnigroup_init() Return Value Check
Summary
CVE-2025-21790: In the Linux kernel, the following vulnerability has been resolved: vxlan: check vxlan_vnigroup_init() return value vxlan_init() must check vxlan_vnigroup_init() success otherwise a crash happens later, spotted by syzbot... Affects linux versions < 6.1.129-1. Fixed in 6.1.129-1. How to fix ↓
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Background
The Linux kernel is the core component of the Linux operating system, responsible for managing system resources and facilitating communication between hardware and software. It supports a wide range of functionalities, including process management, memory management, and networking. The vulnerability in question affects the vxlan (Virtual Extensible LAN) networking feature, which is used to encapsulate Layer 2 Ethernet frames in Layer 4 UDP packets, enabling the creation of virtualized networks over existing infrastructure.
Vulnerability Detail
In the Linux kernel, a critical vulnerability has been identified in the vxlan networking module. The issue arises from the lack of a proper check on the return value of the vxlan_vnigroup_init() function within the vxlan_init() process. If this function fails, it can lead to a crash later in the execution, as evidenced by a general protection fault triggered by a null pointer dereference. This vulnerability could potentially disrupt network operations and lead to system instability.
How To Fix
Minimum fixed version
6.1.129-1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade linuxTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
Currently, there are no specific workarounds available for this vulnerability. The best course of action is to apply the necessary updates as soon as they are available.
Conclusion
The vulnerability identified in the Linux kernel's vxlan networking module poses a significant risk due to its potential to cause system crashes and instability. Users are strongly advised to update their systems to the latest kernel version to ensure protection against this issue. Regular monitoring for vulnerabilities, such as through Vulert, can help maintain system security.
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FAQ
vxlan is a networking feature that allows the encapsulation of Ethernet frames in UDP packets, enabling the creation of virtualized networks over existing infrastructure.
If vxlan_vnigroup_init() fails, it can lead to a crash in the system due to a null pointer dereference, causing instability in network operations.
You can use tools like Vulert, which monitors and alerts for open-source vulnerabilities in your software. You can check your application against this vulnerability using the Vulert playground without any signup.
Yes, a patch has been released for the Linux kernel that addresses this vulnerability. Users should update their kernel to the latest version.
While there are no specific workarounds, it is crucial to plan for an update as soon as possible to mitigate the risks associated with this vulnerability.
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