RHSA-2026:50979 - Security Advisory

Topic

An update for kernel-rt is now available for Red Hat Enterprise Linux 8.

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-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.

Security Fix(es):

• kernel: xen: AMD Zen 2 Processors: Privilege escalation via improper CPU cache isolation (CVE-2025-54518)

Bug Fix(es) and Enhancement(s):

• Kernel crash in bpf_for_each_array_elem() due to missing backport of upstream commit 4b6313cf99b0 (JIRA:RHEL-191844)
• gfs2: xfstests generic/363 failure [rhel-8.10.z] (JIRA:RHEL-214099)
• RHEL8: HYPERV hv_storvsc driver can we add additional code to allow PERSISTENT_RESERVE_IN [RHEL 8.10Z] (JIRA:RHEL-188270)

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.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.

Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture.

Because of this proactive approach, a patch may be associated with a CVE assignment at a future date. Retroactive CVE assignments are always documented in the corresponding errata and on Red Hat's CVE pages. We strongly advise against delaying updates, as doing so may leave your system exposed when protections are already available.

Affected Products

• Red Hat Enterprise Linux for Real Time 8 x86_64
• Red Hat Enterprise Linux for Real Time for NFV 8 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 8.10 x86_64

Fixes

• BZ - 2477784 - CVE-2025-54518 kernel: xen: AMD Zen 2 Processors: Privilege escalation via improper CPU cache isolation

CVEs

• CVE-2025-54518

References

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