RHSA-2021:3088: Important: kernel-rt security and bug fix update

Published Aug 10, 2021
·
Updated

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.Security Fix(es): kernel: race condition in net/can/bcm.c leads to local privilege escalation (CVE-2021-3609) kernel: Improper handling of VMIO|VMPFNMAP vmas in KVM can bypass RO checks (CVE-2021-22543) kernel: out-of-bounds write in xtcompattargetfromuser() in net/netfilter/xtables.c (CVE-2021-22555) 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.Bug Fix(es): kernel-rt: update RT source tree to the RHEL-8.4.z source tree (BZ#1985050) kernel-rt: Merge mm/memcg: Fix kmemcachealloc() performance regression (BZ#1987102)

Affected Software

15 affected componentsFixes available
redhat/kernel-rt<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt-core<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt-debug<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt-debug-core<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt-debug-debuginfo<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt-debug-devel<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt-debug-modules<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt-debug-modules-extra<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt-debuginfo<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt-devel<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt-modules<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt-modules-extra<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt-debug-kvm<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4
redhat/kernel-rt-kvm<4.18.0-305.12.1.rt7.84.el8_4
4.18.0-305.12.1.rt7.84.el8_4

Remediation

Event History

Feb 10, 2026
Advisory Published
via Red Hat·02:53 PM
Data Sourced
via Red Hat·02:53 PM
RemedyDescriptionAffected Software
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Frequently Asked Questions

1

What is the severity of RHSA-2021:3088?

The severity of RHSA-2021:3088 is classified as high due to the potential for local privilege escalation.

2

How do I fix RHSA-2021:3088?

To fix RHSA-2021:3088, upgrade to kernel-rt packages version 4.18.0-305.12.1.rt7.84.el8_4 or later.

3

What vulnerability is addressed in RHSA-2021:3088?

RHSA-2021:3088 addresses a race condition vulnerability in net/can/bcm.c that can lead to local privilege escalation (CVE-2021-3609).

4

Which packages are affected by RHSA-2021:3088?

The affected packages in RHSA-2021:3088 include kernel-rt, kernel-rt-core, kernel-rt-debug, among others, prior to the specified patch version.

5

Is a reboot required after applying the fix for RHSA-2021:3088?

Yes, a reboot is typically required after applying the kernel updates to ensure the changes take effect.

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