CVE-2026-74708: xsk: validate launch-time metadata size

Greg Kroah-Hartman <[email protected]>
Newsgroups org.kernel.vger.linux-cve-announce
Message-ID <2026082237-CVE-2026-74708-e2a3@gregkh>
From: Greg Kroah-Hartman <[email protected]>

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

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

xsk: validate launch-time metadata size

Launch-time metadata extends beyond the first 16 bytes of struct
xsk_tx_metadata. Reject the request when the registered metadata area does
not contain the complete field.

Snapshot the validated flags for the generic transmit path and use that
snapshot for request and completion processing, avoiding inconsistent
decisions if user space changes the flags concurrently.

Note that only xsk_skb_metadata is properly using the flags,
__xsk_buff_get_metadata ignores them. Next commits address that.

The Linux kernel CVE team has assigned CVE-2026-74708 to this issue.


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

	Issue introduced in 6.15 with commit ca4419f15abd19ba8be1e109661b60f9f5b6c9f0 and fixed in 6.18.45 with commit af511afa1d2977f384044df78d6fbf9fba653f7a
	Issue introduced in 6.15 with commit ca4419f15abd19ba8be1e109661b60f9f5b6c9f0 and fixed in 7.1.9 with commit bc63d47611c07b0d5d655fe1a590861931527920
	Issue introduced in 6.15 with commit ca4419f15abd19ba8be1e109661b60f9f5b6c9f0 and fixed in 7.2 with commit 439ce2dddf3d22129b9113a7881637256a35e936
	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-2026-74708
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:
	include/net/xdp_sock_drv.h
	net/xdp/xsk.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/af511afa1d2977f384044df78d6fbf9fba653f7a
	https://git.kernel.org/stable/c/bc63d47611c07b0d5d655fe1a590861931527920
	https://git.kernel.org/stable/c/439ce2dddf3d22129b9113a7881637256a35e936
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.