Critical Vulnerability in Linux Package: Eth: Bnxt Truesize Calculation Flaw
Summary
DEBIAN-CVE-2025-21961: In the Linux kernel, the following vulnerability has been resolved: eth: bnxt: fix truesize for mb-xdp-pass case When mb-xdp is set and return is XDP_PASS, packet is converted from xdp_buff to sk_buff with xdp_update_skb... Affects linux versions < 6.12.20-1. Fixed in 6.12.20-1. How to fix ↓
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Background
The Linux kernel is a core component of the operating system, responsible for managing hardware and system resources. It provides essential functionalities such as process management, memory management, and device control. The kernel is highly modular, allowing for various drivers and subsystems to be integrated. This specific vulnerability affects the 'linux' package in Debian versions 13 and 14, which are widely used in server and desktop environments.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified in the bnxt driver related to the handling of packet sizes when using the mb-xdp feature. When mb-xdp is enabled and the return value is XDP_PASS, the packet is incorrectly converted from xdp_buff to sk_buff due to an erroneous truesize argument passed to the xdp_update_skb_shared_info() function. This miscalculation can lead to system warnings and potential instability, as evidenced by the warning messages generated during operation. The flaw arises from the improper handling of skb_shared_info, which can cause unexpected behavior in packet processing.
How To Fix
Minimum fixed version
6.12.20-1
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
As a temporary workaround, users can avoid using the mb-xdp feature until the package is updated. This can be done by disabling the feature in the network interface settings.
Conclusion
The identified vulnerability in the Linux kernel's bnxt driver poses a risk to systems using the mb-xdp feature. It is crucial to update to the patched version to mitigate potential issues. Users are encouraged to monitor their systems for vulnerabilities using tools like Vulert.
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FAQ
The vulnerability can lead to system warnings and potential instability during packet processing, which may affect network performance.
You can use the Vulert platform to monitor and alert for open-source vulnerabilities. Visit Vulert Scanner to check if your application is affected.
Yes, a patch is available in the form of the updated package version 6.12.20-1 or later.
If an immediate update is not possible, consider disabling the mb-xdp feature as a temporary workaround.
Detailed information can be found in the Debian CVE database at https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-21961.json.
References
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