Use-After-Free Vulnerability in Linux Kernel's eth_skb_pkt_type Function
Summary
CVE-2025-21867: In the Linux kernel, the following vulnerability has been resolved: bpf, test_run: Fix use-after-free issue in eth_skb_pkt_type() KMSAN reported a use-after-free issue in eth_skb_pkt_type()[1]. Affects linux versions < 6.1.133-1. Fixed in 6.1.133-1. How to fix ↓
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Background
The Linux kernel is the core component of many operating systems, providing essential services for hardware and software interactions. It is known for its robustness and flexibility, supporting a wide range of hardware architectures. However, like any complex software, it is susceptible to vulnerabilities that can compromise system integrity and security. This specific vulnerability affects the networking stack, particularly in the handling of Ethernet packets, which is critical for network communication.
Vulnerability Detail
In the Linux kernel, a use-after-free vulnerability was identified in the eth_skb_pkt_type function. This issue arises when the function accesses socket buffer (skb) data that does not contain a valid Ethernet header. The problem is triggered when an invalid user_data argument is passed to the bpf_prog_test_run_xdp function, leading to potential exploitation. If exploited, this vulnerability could allow an attacker to execute arbitrary code or crash the system, posing significant security risks.
How To Fix
Minimum fixed version
6.1.133-1
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 mentioned for this vulnerability. It is best to apply the patch as soon as it becomes available.
Conclusion
The use-after-free vulnerability in the Linux kernel's eth_skb_pkt_type function poses significant security risks, particularly for network operations. It is crucial for users to update their systems to the patched version as soon as it becomes available to mitigate potential threats. Utilizing tools like Vulert can help in monitoring and managing vulnerabilities effectively.
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FAQ
A use-after-free vulnerability occurs when a program continues to use a memory reference after it has been freed, potentially leading to arbitrary code execution or crashes.
You can check if your application is affected by using Vulert, which monitors and alerts for open-source vulnerabilities in real-time. Visit Vulert Scanner to analyze your manifest file.
Exploitation of this vulnerability could allow attackers to execute arbitrary code or crash the system, leading to data breaches or denial of service.
Yes, a patch is available for Debian 13 in version 6.12.17-1. Users of Debian 12 should monitor for updates.
If you cannot apply the patch, ensure that your system is monitored for unusual activity and consider implementing additional security measures until the patch can be applied.
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