Unity Linux 20.1050e Security Update: kernel (UTSA-2026-100109)

medium Nessus Plugin ID 336660

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-2026-100109 advisory.

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

dm cache: fix dirty mapping checking in passthrough mode switching

As mentioned in commit 9b1cc9f251af (dm cache: share cache-metadata object across inactive and active DM tables), dm-cache assumed table reload occurs after suspension, while LVM's table preload breaks this assumption. The dirty mapping check for passthrough mode was designed around this assumption and is performed during table creation, causing the check to fail with preload while metadata updates are ongoing. This risks loading dirty mappings into passthrough mode, resulting in data loss.

Reproduce steps:

1. Create a writeback cache with zero migration_threshold to produce dirty mappings

dmsetup create cmeta --table 0 8192 linear /dev/sdc 0 dmsetup create cdata --table 0 131072 linear /dev/sdc 8192 dmsetup create corig --table 0 262144 linear /dev/sdc 262144 dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct dmsetup create cache --table 0 262144 cache /dev/mapper/cmeta /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writeback smq 2 migration_threshold 0

2. Preload a table in passthrough mode

dmsetup reload cache --table 0 262144 cache /dev/mapper/cmeta /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 passthrough smq 0

3. Write to the first cache block to make it dirty

fio --filename=/dev/mapper/cache --name=populate --rw=write --bs=4k
--direct=1 --size=64k

4. Resume the inactive table. Now it's possible to load the dirty block into passthrough mode.

dmsetup resume cache

Fix by moving the checks to the preresume phase to support table preloading. Also remove the unused function dm_cache_metadata_all_clean.

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: Medium

ID: 336660

File Name: unity_linux_UTSA-2026-100109.nasl

Version: 1.1

Type: Local

Family: Unity Linux Local Security Checks

Published: 8/17/2026

Updated: 8/17/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.76

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-2026-53061

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/cpu, Host/UOS-Server/release, Host/UOS-Server/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 8/13/2026

Vulnerability Publication Date: 6/22/2026

Reference Information

CVE: CVE-2026-53061

Detections

Analytics