Unity Linux 20.1070e Security Update: kernel (UTSA-2025-987628)

medium Nessus Plugin ID 270958

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-2025-987628 advisory.

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

nbd: fix race between nbd_alloc_config() and module removal

When nbd module is being removing, nbd_alloc_config() may be called concurrently by nbd_genl_connect(), although try_module_get() will return false, but nbd_alloc_config() doesn't handle it.

The race may lead to the leak of nbd_config and its related resources (e.g, recv_workq) and oops in nbd_read_stat() due to the unload of nbd module as shown below:

BUG: kernel NULL pointer dereference, address: 0000000000000040 Oops: 0000 [#1] SMP PTI CPU: 5 PID: 13840 Comm: kworker/u17:33 Not tainted 5.14.0+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) Workqueue: knbd16-recv recv_work [nbd] RIP: 0010:nbd_read_stat.cold+0x130/0x1a4 [nbd] Call Trace:
recv_work+0x3b/0xb0 [nbd] process_one_work+0x1ed/0x390 worker_thread+0x4a/0x3d0 kthread+0x12a/0x150 ret_from_fork+0x22/0x30

Fixing it by checking the return value of try_module_get() in nbd_alloc_config(). As nbd_alloc_config() may return ERR_PTR(-ENODEV), assign nbd->config only when nbd_alloc_config() succeeds to ensure the value of nbd->config is binary (valid or NULL).

Also adding a debug message to check the reference counter of nbd_config during module removal.

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: 270958

File Name: unity_linux_UTSA-2025-987628.nasl

Version: 1.1

Type: local

Family: Unity Linux Local Security Checks

Published: 10/21/2025

Updated: 10/21/2025

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.1

CVSS v2

Risk Factor: Low

Base Score: 3.8

Temporal Score: 2.8

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

CVSS Score Source: CVE-2022-49300

CVSS v3

Risk Factor: Medium

Base Score: 4.7

Temporal Score: 4.1

Vector: CVSS:3.0/AV:L/AC:H/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: 10/15/2025

Vulnerability Publication Date: 7/15/2022

Reference Information

CVE: CVE-2022-49300

Detections

Analytics