Unity Linux 20.1050a Security Update: kernel (UTSA-2026-104567)

critical Nessus Plugin ID 339577

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-2026-104567 advisory.

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

tipc: fix UAF in tipc_l2_send_msg()

Syzbot reported a slab-use-after-free in ipvlan_hard_header() when called from tipc_l2_send_msg().

The root cause is that tipc_disable_l2_media() calls synchronize_net() while b->media_ptr is still valid. This allows concurrent RCU readers to obtain the device pointer after synchronize_net() has finished.
The pointer is cleared later in bearer_disable(), but without any subsequent synchronization, allowing the device to be freed while still in use by readers.

Fix this by clearing b->media_ptr in tipc_disable_l2_media() before calling synchronize_net().

This is safe to do now because the call order in bearer_disable() was reversed in 0d051bf93c06 (tipc: make bearer packet filtering generic) to call tipc_node_delete_links() (which needs the pointer) before disable_media().

https: //lore.kernel.org/netdev/[email protected]/T/#u

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: 339577

File Name: unity_linux_UTSA-2026-104567.nasl

Version: 1.1

Type: Local

Family: Unity Linux Local Security Checks

Published: 8/26/2026

Updated: 8/26/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.18

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-2026-74255

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: 8/25/2026

Vulnerability Publication Date: 8/11/2026

Reference Information

CVE: CVE-2026-74255

Detections

Analytics