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

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-07-25 · updated 2026-07-30

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.

Affected products

Linux kernel: from 6.11 before 6.12.37; from 6.13 before 6.15.6; 6.16-rc1, 6.16-rc2, 6.16-rc3, 6.16-rc4 — fixed in 6.12.37, 6.15.6

How to fix

Upgrade to a fixed version: Linux kernel 6.12.37, 6.15.6. Check the vendor advisory for mitigations.

References

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