Unity Linux 20.1050e Security Update: kernel (UTSA-2026-006705)

high Nessus Plugin ID 305412

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-2026-006705 advisory.

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

tracing: Limit access to parser->buffer when trace_get_user failed

When the length of the string written to set_ftrace_filter exceeds FTRACE_BUFF_MAX, the following KASAN alarm will be triggered:

BUG: KASAN: slab-out-of-bounds in strsep+0x18c/0x1b0 Read of size 1 at addr ffff0000d00bd5ba by task ash/165

CPU: 1 UID: 0 PID: 165 Comm: ash Not tainted 6.16.0-g6bcdbd62bd56-dirty Hardware name: linux,dummy-virt (DT) Call trace:
show_stack+0x34/0x50 (C) dump_stack_lvl+0xa0/0x158 print_address_description.constprop.0+0x88/0x398 print_report+0xb0/0x280 kasan_report+0xa4/0xf0
__asan_report_load1_noabort+0x20/0x30 strsep+0x18c/0x1b0 ftrace_process_regex.isra.0+0x100/0x2d8 ftrace_regex_release+0x484/0x618
__fput+0x364/0xa58
____fput+0x28/0x40 task_work_run+0x154/0x278 do_notify_resume+0x1f0/0x220 el0_svc+0xec/0xf0 el0t_64_sync_handler+0xa0/0xe8 el0t_64_sync+0x1ac/0x1b0

The reason is that trace_get_user will fail when processing a string longer than FTRACE_BUFF_MAX, but not set the end of parser->buffer to 0.
Then an OOB access will be triggered in ftrace_regex_release-> ftrace_process_regex->strsep->strpbrk. We can solve this problem by limiting access to parser->buffer when trace_get_user failed.

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?1a14e2b8

http://www.nessus.org/u?9563cff9

https://nvd.nist.gov/vuln/detail/CVE-2025-39683

Plugin Details

Severity: High

ID: 305412

File Name: unity_linux_UTSA-2026-006705.nasl

Version: 1.1

Type: Local

Published: 4/8/2026

Updated: 4/8/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.0

CVSS v2

Risk Factor: Medium

Base Score: 6.2

Temporal Score: 4.6

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

CVSS Score Source: CVE-2025-39683

CVSS v3

Risk Factor: High

Base Score: 7.1

Temporal Score: 6.2

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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: 4/8/2026

Vulnerability Publication Date: 6/10/2025

Reference Information

CVE: CVE-2025-39683