Detections
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RHEL 8 : microcode_ctl (RHSA-2026:65147)

high Nessus Plugin ID 343881

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Synopsis

The remote Red Hat host is missing one or more security updates.

Description

The remote Redhat Enterprise Linux 8 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2026:65147 advisory.

 The microcode_ctl packages provide microcode updates for Intel and AMD processors.

 Security Fix(es):

 * kernel: hypervisor: Intel Processors: Privilege escalation in Ring 0 via improper value handling (CVE-2025-35973)

 * kernel: microcode_ctl: Intel Xeon 6 Processors: Privilege escalation via improper memory range handling in SMM (CVE-2025-31936)

 Bug Fix(es) and Enhancement(s):

 * [RHEL 8] Update Intel CPU microcode to the latest version (JIRA:RHEL-240770)

 For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected microcode_ctl package.

See Also

https://access.redhat.com/errata/RHSA-2026:65147

https://access.redhat.com/security/updates/classification/#important

https://bugzilla.redhat.com/show_bug.cgi?id=2514104

https://bugzilla.redhat.com/show_bug.cgi?id=2514115

https://issues.redhat.com/browse/RHEL-240770

http://www.nessus.org/u?9a8151ee

Plugin Details

Severity: High

ID: 343881

File Name: redhat-RHSA-2026-65147.nasl

Version: 1.3

Type: Local

Agent: unix

Published: 9/8/2026

Updated: 9/22/2026

Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.8

Percentile: 57.82

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: Medium

Base Score: 5.3

Temporal Score: 3.9

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

CVSS Score Source: CVE-2025-31936

CVSS v3

Risk Factor: Medium

Base Score: 5.7

Temporal Score: 5

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

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

CVSS v4

Risk Factor: High

Base Score: 7

Threat Score: 3.7

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:rhel_eus:8.10, p-cpe:/a:redhat:enterprise_linux:microcode_ctl

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

Exploit Ease: No known exploits are available

Patch Publication Date: 9/8/2026

Vulnerability Publication Date: 8/11/2026

Reference Information

CVE: CVE-2025-31936, CVE-2025-35973

CWE: 266, 823

RHSA: 2026:65147