RHSA-2021:4871 — Security Advisory
Red Hat Security Advisory: kernel security and bug fix update
Severity
ImportantRed Hat Product Security
Products
Official CSAF product identity
Published · December 1, 2021
Updated · August 7, 2026
Topic
An update for kernel is now available for Red Hat Enterprise Linux 8.2 Extended Update Support.
Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.
Description
The kernel packages contain the Linux kernel, the core of any Linux operating system.
Security Fix(es):
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kernel: use-after-free in drivers/infiniband/core/ucma.c ctx use-after-free (CVE-2020-36385)
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kernel: timer tree corruption leads to missing wakeup and system freeze (CVE-2021-20317)
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):
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[IBM 8.4] [P10] P10 hardware counter (performance counters/perf:) support (BZ#1994075)
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RHEL8.1 Snapshot1 - [4.18.0-128.el8.ppc64le] [ Brazos 31TB/192 Core ] While running upstream kernel selftest case system crashed (TM) (BZ#1996057)
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[kernel-debug] WARNING: possible circular locking dependency detected (module_mutex & text_mutex) (BZ#2013777)