CVE-2026-90337: serial: core: do fallible allocations before the console can be registered

CVE-2026-90337: serial: core: do fallible allocations before the console can be registered

[Greg Kroah-Hartman]

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

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

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

serial: core: do fallible allocations before the console can be registered

serial_core_add_one_port() allocates uport->tty_groups after
uart_configure_port(), which may register the console. If the allocation
fails, the driver unwinds the port while its console remains registered.
The earlier uport->name allocation has a related failure path that leaves
state->uart_port linked to a port being freed.

Failslab reproduced a NULL dereference in PL011 console output and a KASAN
use-after-free in i.MX console output after failed binds.

Allocate the name and tty_groups before linking the port and configuring
it. Reserve space for the optional driver attribute group because
config_port() may populate uport->attr_group during configuration.

The Linux kernel CVE team has assigned CVE-2026-90337 to this issue.


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

	Issue introduced in 3.17 with commit 266dcff03eed0050b6af11aaf2a61ab837d7ba3f and fixed in 7.2.6 with commit c2aec15f78b2e6ccd9b94216a901248511355982
	Issue introduced in 3.17 with commit 266dcff03eed0050b6af11aaf2a61ab837d7ba3f and fixed in 7.3-rc1 with commit 1a0e4fbce5d9c1bc179a35a2fd9ed142664299e3

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-2026-90337
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:
	drivers/tty/serial/serial_core.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/c2aec15f78b2e6ccd9b94216a901248511355982
	https://git.kernel.org/stable/c/1a0e4fbce5d9c1bc179a35a2fd9ed142664299e3