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Unity Linux 20.1070e Security Update: kernel (UTSA-2025-992694)

medium Nessus Plugin ID 280203

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-2025-992694 advisory.

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

 usb: gadget: u_audio: don't let userspace block driver unbind

 In the unbind callback for f_uac1 and f_uac2, a call to snd_card_free() via g_audio_cleanup() will disconnect the card and then wait for all resources to be released, which happens when the refcount falls to zero.
 Since userspace can keep the refcount incremented by not closing the relevant file descriptor, the call to unbind may block indefinitely.
 This can cause a deadlock during reboot, as evidenced by the following blocked task observed on my machine:

 task:reboot state:D stack:0 pid:2827 ppid:569 flags:0x0000000c Call trace:
 __switch_to+0xc8/0x140
 __schedule+0x2f0/0x7c0 schedule+0x60/0xd0 schedule_timeout+0x180/0x1d4 wait_for_completion+0x78/0x180 snd_card_free+0x90/0xa0 g_audio_cleanup+0x2c/0x64 afunc_unbind+0x28/0x60 ...
 kernel_restart+0x4c/0xac
 __do_sys_reboot+0xcc/0x1ec
 __arm64_sys_reboot+0x28/0x30 invoke_syscall+0x4c/0x110 ...

 The issue can also be observed by opening the card with arecord and then stopping the process through the shell before unbinding:

 # arecord -D hw:UAC2Gadget -f S32_LE -c 2 -r 48000 /dev/null Recording WAVE '/dev/null' : Signed 32 bit Little Endian, Rate 48000 Hz, Stereo ^Z[1]+ Stopped arecord -D hw:UAC2Gadget -f S32_LE -c 2 -r 48000 /dev/null # echo gadget.0 > /sys/bus/gadget/drivers/configfs-gadget/unbind (observe that the unbind command never finishes)

 Fix the problem by using snd_card_free_when_closed() instead, which will still disconnect the card as desired, but defer the task of freeing the resources to the core once userspace closes its file descriptor.

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?66463fb4

http://www.nessus.org/u?e01e2b93

https://nvd.nist.gov/vuln/detail/CVE-2023-53045

Plugin Details

Severity: Medium

ID: 280203

File Name: unity_linux_UTSA-2025-992694.nasl

Version: 1.1

Type: local

Published: 12/30/2025

Updated: 12/30/2025

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

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

CVSS Score Source: CVE-2023-53045

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 4.8

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

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

Vulnerability Information

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

Exploit Ease: No known exploits are available

Patch Publication Date: 12/30/2025

Vulnerability Publication Date: 5/2/2025

Reference Information

CVE: CVE-2023-53045