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Unity Linux 20.1070e Security Update: kernel (UTSA-2025-987291)
medium Nessus Plugin ID 268106
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-2025-987291 advisory.In the Linux kernel, the following vulnerability has been resolved:
audit: improve robustness of the audit queue handling
If the audit daemon were ever to get stuck in a stopped state the kernel's kauditd_thread() could get blocked attempting to send audit records to the userspace audit daemon. With the kernel thread blocked it is possible that the audit queue could grow unbounded as certain audit record generating events must be exempt from the queue limits else the system enter a deadlock state.
This patch resolves this problem by lowering the kernel thread's socket sending timeout from MAX_SCHEDULE_TIMEOUT to HZ/10 and tweaks the kauditd_send_queue() function to better manage the various audit queues when connection problems occur between the kernel and the audit daemon. With this patch, the backlog may temporarily grow beyond the defined limits when the audit daemon is stopped and the system is under heavy audit pressure, but kauditd_thread() will continue to make progress and drain the queues as it would for other connection problems. For example, with the audit daemon put into a stopped state and the system configured to audit every syscall it was still possible to shutdown the system without a kernel panic, deadlock, etc.; granted, the system was slow to shutdown but that is to be expected given the extreme pressure of recording every syscall.
The timeout value of HZ/10 was chosen primarily through experimentation and this developer's gut feeling. There is likely no one perfect value, but as this scenario is limited in scope (root privileges would be needed to send SIGSTOP to the audit daemon), it is likely not worth exposing this as a tunable at present. This can always be done at a later date if it proves necessary.
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.
See Also
http://www.nessus.org/u?f33d776f
Plugin Details
Severity: Medium
ID: 268106
File Name: unity_linux_UTSA-2025-987291.nasl
Version: 1.1
Type: local
Published: 10/7/2025
Updated: 10/7/2025
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 4.4
CVSS v2
Risk Factor: Medium
Base Score: 4.3
Temporal Score: 3.2
Vector: CVSS2#AV:L/AC:L/Au:M/C:N/I:N/A:C
CVSS Score Source: CVE-2021-47603
CVSS v3
Risk Factor: Medium
Base Score: 4.4
Temporal Score: 3.9
Vector: CVSS:3.0/AV:L/AC:L/PR:H/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/cpu, Host/UOS-Server/release, Host/UOS-Server/rpm-list
Exploit Ease: No known exploits are available
Patch Publication Date: 9/23/2025
Vulnerability Publication Date: 1/28/2022
Reference Information
CVE: CVE-2021-47603