Unity Linux 20.1070a Security Update: kernel (UTSA-2026-143097)

critical Nessus Plugin ID 370688

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-2026-143097 advisory.

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

net/smc: fix socket use-after-free during link group termination

__smc_lgr_terminate() drops conns_lock after finding a connection in lgr->conns_all, but before taking a reference on its socket. The connection is embedded in the socket, and its registration reference protects it only while the connection remains in the tree.

A concurrent close can unregister the connection and drop that reference, freeing the socket before the termination worker reaches sock_hold().

The race is reachable when close overlaps link group termination.
Local stress testing reproduced the use-after-free and KASAN reported:

BUG: KASAN: slab-use-after-free in __smc_lgr_terminate.part.0 [smc] Write of size 4 by task kworker/3:3 Workqueue: events smc_lgr_terminate_work [smc]
__smc_lgr_terminate.part.0 [smc]

The socket was allocated by smc_create(), freed through slab_free_after_rcu_debug(), and was followed by:

refcount_t: addition on 0; use-after-free.
__smc_lgr_terminate.part.0 [smc]

Take the socket reference while conns_lock still protects the tree entry.
The unregister path then cannot drop the last reference until termination has finished using the socket.

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.

Plugin Details

Severity: Critical

ID: 370688

File Name: unity_linux_UTSA-2026-143097.nasl

Version: 1.1

Type: Local

Family: Unity Linux Local Security Checks

Published: 10/22/2026

Updated: 10/22/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.6

Percentile: 98.26

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

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

CVSS Score Source: CVE-2026-74493

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/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: 10/23/2026

Vulnerability Publication Date: 8/11/2026

Reference Information

CVE: CVE-2026-74493

Detections

Analytics