CVE-2026-53010: ksmbd: fix use-after-free in smb2_open during durable reconnect

CVE-2026-53010: ksmbd: fix use-after-free in smb2_open during durable reconnect

[Greg Kroah-Hartman]

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

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

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

ksmbd: fix use-after-free in smb2_open during durable reconnect

In smb2_open, the call to ksmbd_put_durable_fd(fp) drops the reference
to the durable file descriptor early during the durable reconnect
process. If an error occurs subsequently (eg, ksmbd_iov_pin_rsp fails)
or a scavenger accesses the file, it leads to a use-after-free when
accessing fp properties (eg fp->create_time).

Move the single put to the end of the function below err_out2 so fp
stays valid until smb2_open returns.

The Linux kernel CVE team has assigned CVE-2026-53010 to this issue.


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

	Issue introduced in 6.9 with commit c8efcc786146a951091588e5fa7e3c754850cb3c and fixed in 6.18.33 with commit ce2e164c1c51c3f7813b80f8c926836e896bcbb3
	Issue introduced in 6.9 with commit c8efcc786146a951091588e5fa7e3c754850cb3c and fixed in 7.0.10 with commit 97a0cd55283b4e63fd92804da91c8d9896adcad9
	Issue introduced in 6.9 with commit c8efcc786146a951091588e5fa7e3c754850cb3c and fixed in 7.1 with commit 1baff47b81f94f9231c91236aa511420d0e266b9
	Issue introduced in 6.6.32 with commit 8df4bcdb0a4232192b2445256c39b787d58ef14d

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-2026-53010
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/smb2pdu.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/ce2e164c1c51c3f7813b80f8c926836e896bcbb3
	https://git.kernel.org/stable/c/97a0cd55283b4e63fd92804da91c8d9896adcad9
	https://git.kernel.org/stable/c/1baff47b81f94f9231c91236aa511420d0e266b9