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Unity Linux 20.1060e / 20.1070e Security Update: kernel (UTSA-2026-004786)

medium Nessus Plugin ID 290198

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-2026-004786 advisory.

 The Linux kernel allows userspace processes to enable mitigations by calling prctl with PR_SET_SPECULATION_CTRL which disables the speculation feature as well as by using seccomp. We had noticed that on VMs of at least one major cloud provider, the kernel still left the victim process exposed to attacks in some cases even after enabling the spectre-BTI mitigation with prctl. The same behavior can be observed on a bare-metal machine when forcing the mitigation to IBRS on boot command line.

 This happened because when plain IBRS was enabled (not enhanced IBRS), the kernel had some logic that determined that STIBP was not needed. The IBRS bit implicitly protects against cross-thread branch target injection. However, with legacy IBRS, the IBRS bit was cleared on returning to userspace, due to performance reasons, which disabled the implicit STIBP and left userspace threads vulnerable to cross- thread branch target injection against which STIBP protects.

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?31a9d6aa

https://nvd.nist.gov/vuln/detail/CVE-2023-1998

Plugin Details

Severity: Medium

ID: 290198

File Name: unity_linux_UTSA-2026-004786.nasl

Version: 1.1

Type: local

Published: 1/16/2026

Updated: 1/16/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.2

CVSS v2

Risk Factor: Low

Base Score: 3.8

Temporal Score: 3

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

CVSS Score Source: CVE-2023-1998

CVSS v3

Risk Factor: Medium

Base Score: 5.6

Temporal Score: 5.1

Vector: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

Required KB Items: Host/local_checks_enabled, Host/UOS-Server/release, Host/UOS-Server/rpm-list, Host/cpu

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 1/16/2026

Vulnerability Publication Date: 3/21/2023

Reference Information

CVE: CVE-2023-1998