CVE-2026-74707: xsk: validate metadata when processing requests

From: Greg Kroah-Hartman <[email protected]>

Description
===========

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

xsk: validate metadata when processing requests

The zero-copy path validates TX metadata while obtaining the descriptor
context, then reads it again later when preparing the hardware request.
User space can change the metadata between those operations and bypass the
original validation.

Validate the metadata in xsk_tx_metadata_request() and use the resulting
flags snapshot for every feature check. Read request fields once so all
zero-copy drivers process only values observed after successful
validation.

The Linux kernel CVE team has assigned CVE-2026-74707 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.15 with commit ca4419f15abd19ba8be1e109661b60f9f5b6c9f0 and fixed in 6.18.45 with commit 5fd121971912dee2f5af1efec64462ac722deb17
	Issue introduced in 6.15 with commit ca4419f15abd19ba8be1e109661b60f9f5b6c9f0 and fixed in 7.1.9 with commit 0cc7aa6e0d19027fdd42e6fbd156267ac1e3bbba
	Issue introduced in 6.15 with commit ca4419f15abd19ba8be1e109661b60f9f5b6c9f0 and fixed in 7.2 with commit 849b1664dbda1cf6c63e0fd4f9dec23782b8c851
	Issue introduced in 6.14.2 with commit d9d736c416c9a85f84e15435ba82a177262e745b

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-74707
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/net/ethernet/intel/igc/igc_main.c
	drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c
	drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
	include/net/libeth/xsk.h
	include/net/xdp_sock_drv.h
	net/xdp/xsk_buff_pool.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/5fd121971912dee2f5af1efec64462ac722deb17
	https://git.kernel.org/stable/c/0cc7aa6e0d19027fdd42e6fbd156267ac1e3bbba
	https://git.kernel.org/stable/c/849b1664dbda1cf6c63e0fd4f9dec23782b8c851