CVE-2026-74673: Input: evdev - fix information leak in evdev_pass_values()

From: Greg Kroah-Hartman <[email protected]>

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

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

Input: evdev - fix information leak in evdev_pass_values()

In evdev_pass_values(), the input_event structure is allocated on the
kernel stack and populated field-by-field. However, it is never fully
initialized. On architectures where struct input_event contains explicit
or implicit padding (such as the 32-bit __pad field on SPARC64), these
padding bytes are left uninitialized.

When this event structure is subsequently passed to the client buffer
and later copied to userspace, the uninitialized padding bytes leak
kernel stack memory, potentially exposing sensitive information.

Similar issues exist in __evdev_queue_syn_dropped and __pass_event.

Fix this by explicitly zeroing the entire event structure with memset()
before populating its fields. This ensures all padding bytes are cleared
before the data crosses the security boundary.

The Linux kernel CVE team has assigned CVE-2026-74673 to this issue.


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

	Fixed in 5.10.265 with commit d2e3839419ac4047835762c4d7712bda1101b57e
	Fixed in 5.15.216 with commit c6d5fa46c1ee25d068fc730fd377f0f54188d290
	Fixed in 6.1.183 with commit e748811d9b80a3e101110ff4b3c612e5fca54d98
	Fixed in 6.6.152 with commit 06a286b320236508d02ab2ccc9496352748652a8
	Fixed in 6.12.104 with commit 7d17e9454a9af3ec7aebb88b41a9deedd5b19a6b
	Fixed in 6.18.45 with commit bd3c4108a56de34380edab670065e86283cb3029
	Fixed in 7.1.9 with commit 7e55ca1080f09d9f7112c7f20ac31f682c1f2374
	Fixed in 7.2 with commit 90f305f2c7a30257c683e13f4bf7c798eea992a0

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-2026-74673
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/input/evdev.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/d2e3839419ac4047835762c4d7712bda1101b57e
	https://git.kernel.org/stable/c/c6d5fa46c1ee25d068fc730fd377f0f54188d290
	https://git.kernel.org/stable/c/e748811d9b80a3e101110ff4b3c612e5fca54d98
	https://git.kernel.org/stable/c/06a286b320236508d02ab2ccc9496352748652a8
	https://git.kernel.org/stable/c/7d17e9454a9af3ec7aebb88b41a9deedd5b19a6b
	https://git.kernel.org/stable/c/bd3c4108a56de34380edab670065e86283cb3029
	https://git.kernel.org/stable/c/7e55ca1080f09d9f7112c7f20ac31f682c1f2374
	https://git.kernel.org/stable/c/90f305f2c7a30257c683e13f4bf7c798eea992a0