CVE-2026-74269

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

bnxt: fix head underflow on XDP head-grow

The xdp.py test test_xdp_native_adjst_head_grow_data crashes when run on

a bnxt machine (and also crashes in NIPA).

It seems that the bug is an underflow in bnxt_rx_multi_page_skb, which

builds the skb head:

napi_build_skb(data_ptr - bp->rx_offset, rxr->rx_page_size);

The problem with this expression is that in page mode, rx_offset is:

bp->rx_offset = NET_IP_ALIGN + XDP_PACKET_HEADROOM;

Which evaluates (at least on x86_64) to 258.

The test test_xdp_native_adjst_head_grow_data tests a case where the

head is adjusted by -256.

When this test runs, data_ptr is shifted to frag_start + 2 (where

frag_start = page_address(page) + offset).

Then, bnxt_rx_multi_page_skb is invoked and the napi_build_skb

expression subtracts 258, landing at an address before frag_start. This

could be either the previous fragment or the previous physical page when

the offset is < 256 (e.g. if

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References