CVE-2026-74710: xsk: require at least 16 bytes of TX metadata

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

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

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

xsk: require at least 16 bytes of TX metadata

AF_XDP accepts a TX metadata length as small as eight bytes, but every
supported request needs the flags plus at least one eight-byte request
field. Such short metadata also lets the kernel read beyond the registered
area.

Require 16 bytes rather than sizeof(struct xsk_tx_metadata) to preserve
compatibility with applications that do not use launch-time metadata.

The Linux kernel CVE team has assigned CVE-2026-74710 to this issue.


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

	Issue introduced in 6.8 with commit 341ac980eab90ac1f6c22ee9f9da83ed9604d899 and fixed in 6.12.104 with commit 21b8536aee819792f1b4b38b9aacf2a073025d49
	Issue introduced in 6.8 with commit 341ac980eab90ac1f6c22ee9f9da83ed9604d899 and fixed in 6.18.45 with commit 642c6e73fce17fdca93a5793c4d22359fda866d7
	Issue introduced in 6.8 with commit 341ac980eab90ac1f6c22ee9f9da83ed9604d899 and fixed in 7.1.9 with commit cfb9d2976b277e554e28c165e3eff4b4a8ea10bd
	Issue introduced in 6.8 with commit 341ac980eab90ac1f6c22ee9f9da83ed9604d899 and fixed in 7.2 with commit 1bb30b181d9f0484e141f8411e15ed906d5c6780

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-2026-74710
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:
	net/xdp/xdp_umem.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/21b8536aee819792f1b4b38b9aacf2a073025d49
	https://git.kernel.org/stable/c/642c6e73fce17fdca93a5793c4d22359fda866d7
	https://git.kernel.org/stable/c/cfb9d2976b277e554e28c165e3eff4b4a8ea10bd
	https://git.kernel.org/stable/c/1bb30b181d9f0484e141f8411e15ed906d5c6780