RHSA-2026:49030 - Security Advisory

Topic

An update for kernel is now available for Red Hat Enterprise Linux 10.0 Extended Update Support.

Red Hat Product Security has rated this update as having a security impact of Moderate. 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):

• kernel: KVM: x86: Don't (re)check L1 intercepts when completing userspace I/O (CVE-2025-40026)
• kernel: KVM: x86/mmu: Ensure hugepage is in by slot before checking max mapping level (CVE-2026-63807)

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 x86_64 - Extended Update Support 10.0 x86_64
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 10.0 s390x
• Red Hat Enterprise Linux for Power, little endian - Extended Update Support 10.0 ppc64le
• Red Hat Enterprise Linux for ARM 64 - Extended Update Support 10.0 aarch64
• Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support 10.0 x86_64
• Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support 10.0 ppc64le
• Red Hat CodeReady Linux Builder for IBM z Systems - Extended Update Support 10.0 s390x
• Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support 10.0 aarch64
• Red Hat Enterprise Linux for ARM 64 - 4 years of updates 10.0 aarch64
• Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 10.0 s390x
• Red Hat Enterprise Linux for Power, little endian - 4 years of support 10.0 ppc64le
• Red Hat Enterprise Linux for x86_64 - 4 years of updates 10.0 x86_64

Fixes

• BZ - 2406712 - CVE-2025-40026 kernel: KVM: x86: Don't (re)check L1 intercepts when completing userspace I/O
• BZ - 2502249 - CVE-2026-63807 kernel: KVM: x86/mmu: Ensure hugepage is in by slot before checking max mapping level

CVEs

• CVE-2025-40026
• CVE-2026-63807
• CVE-2026-64561

References

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