Unity Linux 20.1050e Security Update: kernel (UTSA-2026-006741)

high Nessus Plugin ID 305400

Synopsis

The Unity Linux host is missing one or more security updates.

Description

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-006741 advisory.

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

HID: asus: fix UAF via HID_CLAIMED_INPUT validation

After hid_hw_start() is called hidinput_connect() will eventually be called to set up the device with the input layer since the HID_CONNECT_DEFAULT connect mask is used. During hidinput_connect() all input and output reports are processed and corresponding hid_inputs are allocated and configured via hidinput_configure_usages(). This process involves slot tagging report fields and configuring usages by setting relevant bits in the capability bitmaps. However it is possible that the capability bitmaps are not set at all leading to the subsequent hidinput_has_been_populated() check to fail leading to the freeing of the hid_input and the underlying input device.

This becomes problematic because a malicious HID device like a ASUS ROG N-Key keyboard can trigger the above scenario via a specially crafted descriptor which then leads to a user-after-free when the name of the freed input device is written to later on after hid_hw_start(). Below, report 93 intentionally utilises the HID_UP_UNDEFINED Usage Page which is skipped during usage configuration, leading to the frees.

0x05, 0x0D, // Usage Page (Digitizer) 0x09, 0x05, // Usage (Touch Pad) 0xA1, 0x01, // Collection (Application) 0x85, 0x0D, // Report ID (13) 0x06, 0x00, 0xFF, // Usage Page (Vendor Defined 0xFF00) 0x09, 0xC5, // Usage (0xC5) 0x15, 0x00, // Logical Minimum (0) 0x26, 0xFF, 0x00, // Logical Maximum (255) 0x75, 0x08, // Report Size (8) 0x95, 0x04, // Report Count (4) 0xB1, 0x02, // Feature (Data,Var,Abs) 0x85, 0x5D, // Report ID (93) 0x06, 0x00, 0x00, // Usage Page (Undefined) 0x09, 0x01, // Usage (0x01) 0x15, 0x00, // Logical Minimum (0) 0x26, 0xFF, 0x00, // Logical Maximum (255) 0x75, 0x08, // Report Size (8) 0x95, 0x1B, // Report Count (27) 0x81, 0x02, // Input (Data,Var,Abs) 0xC0, // End Collection

Below is the KASAN splat after triggering the UAF:

[ 21.672709] ================================================================== [ 21.673700] BUG: KASAN: slab-use-after-free in asus_probe+0xeeb/0xf80 [ 21.673700] Write of size 8 at addr ffff88810a0ac000 by task kworker/1:2/54 [ 21.673700] [ 21.673700] CPU: 1 UID: 0 PID: 54 Comm: kworker/1:2 Not tainted 6.16.0-rc4-g9773391cf4dd-dirty #36 PREEMPT(voluntary) [ 21.673700] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 [ 21.673700] Call Trace:
[ 21.673700] <TASK> [ 21.673700] dump_stack_lvl+0x5f/0x80 [ 21.673700] print_report+0xd1/0x660 [ 21.673700] kasan_report+0xe5/0x120 [ 21.673700] __asan_report_store8_noabort+0x1b/0x30 [ 21.673700] asus_probe+0xeeb/0xf80 [ 21.673700] hid_device_probe+0x2ee/0x700 [ 21.673700] really_probe+0x1c6/0x6b0 [ 21.673700] __driver_probe_device+0x24f/0x310 [ 21.673700] driver_probe_device+0x4e/0x220 [...] [ 21.673700] [ 21.673700] Allocated by task 54:
[ 21.673700] kasan_save_stack+0x3d/0x60 [ 21.673700] kasan_save_track+0x18/0x40 [ 21.673700] kasan_save_alloc_info+0x3b/0x50 [ 21.673700] __kasan_kmalloc+0x9c/0xa0 [ 21.673700] __kmalloc_cache_noprof+0x139/0x340 [ 21.673700] input_allocate_device+0x44/0x370 [ 21.673700] hidinput_connect+0xcb6/0x2630 [ 21.673700] hid_connect+0xf74/0x1d60 [ 21.673700] hid_hw_start+0x8c/0x110 [ 21.673700] asus_probe+0x5a3/0xf80 [ 21.673700] hid_device_probe+0x2ee/0x700 [ 21.673700] really_probe+0x1c6/0x6b0 [ 21.673700] __driver_probe_device+0x24f/0x310 [ 21.673700] driver_probe_device+0x4e/0x220 [...] [ 21.673700] [ 21.673700] Freed by task 54:
[ 21.673700] kasan_save_stack+0x3d/0x60 [ 21.673700] kasan_save_track+0x18/0x40 [ 21.673700] kasan_save_free_info+0x3f/0x60 [ 21.673700] __kasan_slab_free+0x3c/0x50 [ 21.673700] kfre
---truncated---

Tenable has extracted the preceding description block directly from the Unity Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected kernel package.

See Also

http://www.nessus.org/u?49bdac4c

http://www.nessus.org/u?8cdd36e3

https://nvd.nist.gov/vuln/detail/CVE-2025-39824

Plugin Details

Severity: High

ID: 305400

File Name: unity_linux_UTSA-2026-006741.nasl

Version: 1.1

Type: Local

Published: 4/8/2026

Updated: 4/8/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

Vector: CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C

CVSS Score Source: CVE-2025-39824

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/UOS-Server/release, Host/UOS-Server/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 4/8/2026

Vulnerability Publication Date: 9/16/2025

Reference Information

CVE: CVE-2025-39824