CVE-2026-89584: block: validate user space vectors during extraction

CVE-2026-89584: block: validate user space vectors during extraction

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

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

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

block: validate user space vectors during extraction

The bio-based drivers don't necessarily check the alignment split, and
stacking block drivers don't always handle a misalignment detected after
submitting the bio. Validate user vectors against the device's
dma_alignment as the bio is built from the iov_iter, rejecting
misaligned early with -EINVAL.

The Linux kernel CVE team has assigned CVE-2026-89584 to this issue.


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

	Issue introduced in 6.18 with commit 5ff3f74e145adc79b49668adb8de276446acf6be and fixed in 7.2.4 with commit d44a97a3b1c00cc571245124e23e5ceb0a0225a0
	Issue introduced in 6.18 with commit 5ff3f74e145adc79b49668adb8de276446acf6be and fixed in 7.3-rc1 with commit 14b007e178811db72fbb1ebb3535160db6ec1e6a

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-2026-89584
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:
	block/bio.c
	block/blk-map.c
	block/fops.c
	fs/iomap/direct-io.c
	include/linux/bio.h
	include/linux/uio.h
	lib/iov_iter.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/d44a97a3b1c00cc571245124e23e5ceb0a0225a0
	https://git.kernel.org/stable/c/14b007e178811db72fbb1ebb3535160db6ec1e6a