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Unity Linux 20.1070e Security Update: kernel (UTSA-2025-987014)

medium Nessus Plugin ID 268413

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-2025-987014 advisory.

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

 mm/slub: actually fix freelist pointer vs redzoning

 It turns out that SLUB redzoning (slub_debug=Z) checks from s->object_size rather than from s->inuse (which is normally bumped to make room for the freelist pointer), so a cache created with an object size less than 24 would have the freelist pointer written beyond s->object_size, causing the redzone to be corrupted by the freelist pointer. This was very visible with slub_debug=ZF:

 BUG test (Tainted: G B ): Right Redzone overwritten
 -----------------------------------------------------------------------------

 INFO: 0xffff957ead1c05de-0xffff957ead1c05df @offset=1502. First byte 0x1a instead of 0xbb INFO: Slab 0xffffef3950b47000 objects=170 used=170 fp=0x0000000000000000 flags=0x8000000000000200 INFO: Object 0xffff957ead1c05d8 @offset=1496 fp=0xffff957ead1c0620

 Redzone (____ptrval____): bb bb bb bb bb bb bb bb ........
 Object (____ptrval____): 00 00 00 00 00 f6 f4 a5 ........
 Redzone (____ptrval____): 40 1d e8 1a aa @....
 Padding (____ptrval____): 00 00 00 00 00 00 00 00 ........

 Adjust the offset to stay within s->object_size.

 (Note that no caches of in this size range are known to exist in the kernel currently.)

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?99192f48

http://www.nessus.org/u?0f837606

https://nvd.nist.gov/vuln/detail/CVE-2021-47221

Plugin Details

Severity: Medium

ID: 268413

File Name: unity_linux_UTSA-2025-987014.nasl

Version: 1.2

Type: local

Published: 10/7/2025

Updated: 10/15/2025

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

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-2021-47221

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: 9/23/2025

Vulnerability Publication Date: 1/28/2022

Reference Information

CVE: CVE-2021-47221