linux-cve-announce - CVE-2025-68758: backlight: led-bl: Add devlink to supplier LEDs

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Message-ID: <2026010550-CVE-2025-68758-a505@gregkh>
Date: Mon,  5 Jan 2026 10:32:54 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68758: backlight: led-bl: Add devlink to supplier LEDs

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

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

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

backlight: led-bl: Add devlink to supplier LEDs

LED Backlight is a consumer of one or multiple LED class devices, but
devlink is currently unable to create correct supplier-producer links when
the supplier is a class device. It creates instead a link where the
supplier is the parent of the expected device.

One consequence is that removal order is not correctly enforced.

Issues happen for example with the following sections in a device tree
overlay:

    // An LED driver chip
    pca9632@62 {
        compatible = "nxp,pca9632";
        reg = <0x62>;

	// ...

        addon_led_pwm: led-pwm@3 {
            reg = <3>;
            label = "addon:led:pwm";
        };
    };

    backlight-addon {
        compatible = "led-backlight";
        leds = <&addon_led_pwm>;
        brightness-levels = <255>;
        default-brightness-level = <255>;
    };

In this example, the devlink should be created between the backlight-addon
(consumer) and the pca9632@62 (supplier). Instead it is created between the
backlight-addon (consumer) and the parent of the pca9632@62, which is
typically the I2C bus adapter.

On removal of the above overlay, the LED driver can be removed before the
backlight device, resulting in:

    Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010
    ...
    Call trace:
     led_put+0xe0/0x140
     devm_led_release+0x6c/0x98

Another way to reproduce the bug without any device tree overlays is
unbinding the LED class device (pca9632@62) before unbinding the consumer
(backlight-addon):

  echo 11-0062 >/sys/bus/i2c/drivers/leds-pca963x/unbind
  echo ...backlight-dock >/sys/bus/platform/drivers/led-backlight/unbind

Fix by adding a devlink between the consuming led-backlight device and the
supplying LED device, as other drivers and subsystems do as well.

The Linux kernel CVE team has assigned CVE-2025-68758 to this issue.


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

	Issue introduced in 5.6 with commit ae232e45acf9621f2c96b41ca3af006ac7552c33 and fixed in 6.12.63 with commit 0e63ea4378489e09eb5e920c8a50c10caacf563a
	Issue introduced in 5.6 with commit ae232e45acf9621f2c96b41ca3af006ac7552c33 and fixed in 6.17.13 with commit 60a24070392ec726ccfe6ad1ca7b0381c8d8f7c9
	Issue introduced in 5.6 with commit ae232e45acf9621f2c96b41ca3af006ac7552c33 and fixed in 6.18.2 with commit 08c9dc6b0f2c68e5e7c374ac4499e321e435d46c
	Issue introduced in 5.6 with commit ae232e45acf9621f2c96b41ca3af006ac7552c33 and fixed in 6.19-rc1 with commit 9341d6698f4cfdfc374fb6944158d111ebe16a9d

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-2025-68758
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/video/backlight/led_bl.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/0e63ea4378489e09eb5e920c8a50c10caacf563a
	https://git.kernel.org/stable/c/60a24070392ec726ccfe6ad1ca7b0381c8d8f7c9
	https://git.kernel.org/stable/c/08c9dc6b0f2c68e5e7c374ac4499e321e435d46c
	https://git.kernel.org/stable/c/9341d6698f4cfdfc374fb6944158d111ebe16a9d