Critical Vulnerability in Linux Kernel: HWTSTAMP_TX_ONESTEP_SYNC Support in ENETC VFs
Summary
CVE-2025-21894: In the Linux kernel, the following vulnerability has been resolved: net: enetc: VFs do not support HWTSTAMP_TX_ONESTEP_SYNC Actually ENETC VFs do not support HWTSTAMP_TX_ONESTEP_SYNC because only ENETC PF can access PMa_... Affects linux versions 5.10.103-1 – 6.9.9-1. No fix is published. How to fix ↓
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Background
The Linux kernel is a core component of many operating systems, providing essential services for hardware and software interactions. It is known for its stability, performance, and extensive hardware support. However, certain configurations, such as the use of ENETC Virtual Functions (VFs), can expose vulnerabilities, particularly in timestamp handling, which can lead to system crashes.
Vulnerability Detail
The vulnerability identified as CVE-2025-21894 arises from the fact that ENETC VFs do not support HWTSTAMP_TX_ONESTEP_SYNC. This limitation exists because only the ENETC Physical Function (PF) can access the PMa_SINGLE_STEP registers. When VFs attempt to utilize one-step timestamp testing, it results in a kernel crash, as indicated by the crash log that shows an inability to handle kernel paging requests. This can lead to system instability and potential data loss.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
Currently, there are no specific workarounds provided for this vulnerability. It is advisable to avoid using ENETC VFs for one-step timestamp testing until the system is updated with the patched version.
Conclusion
CVE-2025-21894 is a significant vulnerability in the Linux kernel that affects systems using ENETC VFs for timestamp handling. It is crucial to apply the necessary updates to prevent system crashes and ensure stability. Regular monitoring for vulnerabilities using tools like Vulert can help maintain system security.
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FAQ
CVE-2025-21894 is a vulnerability in the Linux kernel related to the handling of one-step timestamps in ENETC Virtual Functions, which can lead to system crashes.
If your system uses ENETC VFs and attempts to perform one-step timestamp testing, it may crash, leading to potential data loss and instability.
Yes, a patch is available for Debian 13 in version 6.12.19-1. It is important to update your system to this version to mitigate the vulnerability.
If you cannot update your system, avoid using ENETC VFs for one-step timestamp testing until you can apply the patch.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in your software using just a manifest file like package-lock.json. You can also check if your application is affected by this vulnerability using the Vulert playground.
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