CVE-2026-89792: ksmbd: prevent out-of-bounds reads in share config responses

CVE-2026-89792: ksmbd: prevent out-of-bounds reads in share config responses

[Greg Kroah-Hartman]

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

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

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

ksmbd: prevent out-of-bounds reads in share config responses

Validate IPC share configuration payload sizes before consuming
variable-length fields. Bound veto list parsing and account for
the separator byte when deriving the path length.

The Linux kernel CVE team has assigned CVE-2026-89792 to this issue.


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

	Issue introduced in 6.9 with commit a677ebd8ca2f2632ccdecbad7b87641274e15aac and fixed in 7.2.6 with commit 61a8d06600c8c397f9a7e01940479d4c94a82f5f
	Issue introduced in 6.9 with commit a677ebd8ca2f2632ccdecbad7b87641274e15aac and fixed in 7.3-rc2 with commit f25e93768fcc5d8287e50b1ec52a42e4c276df34
	Issue introduced in 5.15.157 with commit 88b7f1143b15b29cccb8392b4f38e75b7bb3e300
	Issue introduced in 6.1.85 with commit 51a6c2af9d20203ddeeaf73314ba8854b38d01bd
	Issue introduced in 6.6.26 with commit a637fabac554270a851033f5ab402ecb90bc479c
	Issue introduced in 6.8.5 with commit 76af689a45aa44714b46d1a7de4ffdf851ded896

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-2026-89792
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:
	fs/smb/server/mgmt/share_config.c
	fs/smb/server/transport_ipc.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/61a8d06600c8c397f9a7e01940479d4c94a82f5f
	https://git.kernel.org/stable/c/f25e93768fcc5d8287e50b1ec52a42e4c276df34