RHSA-2026:63013 - 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: s390/cpum_sf: Handle CPU hotplug remove during sampling (CVE-2024-57849)
• kernel: smc91x: fix broken irq-context in PREEMPT_RT (CVE-2025-71132)
• kernel: bonding: alb: fix UAF in rlb_arp_recv during bond up/down (CVE-2026-45970)
• kernel: zram: fix use-after-free in zram_bvec_write_partial() (CVE-2026-53185)
• kernel: pNFS: Fix use-after-free in pnfs_update_layout() (CVE-2026-63800)
• kernel: nfsd: fix posix_acl leak on SETACL decode failure (CVE-2026-53397)
• kernel: nfsd: release layout stid on setlease failure (CVE-2026-53399)
• kernel: NFSv4/flexfiles: reject zero filehandle version count (CVE-2026-53392)
• kernel: NFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr (CVE-2026-53391)
• kernel: net: mana: validate rx_req_idx to prevent out-of-bounds array access (CVE-2026-64018)
• kernel: Kernel: Remote out-of-bounds write in RDMA/siw (CVE-2026-64268)
• kernel: NFSv4: include MAY_WRITE in open permission mask for O_TRUNC (CVE-2026-64298)
• kernel: AMD-SN-7061: Safe RET Interrupt Vulnerability (CVE-2026-68480)
• kernel: net: ipv6: use-after-free in fib6_rule_suppress due to stale res->rt6 pointer (CVE-2026-74581)

Bug Fix(es) and Enhancement(s):

• qede: build_skb failure causes off-by-one BD ring corruption and kernel panic [rhel-8.10.z] (JIRA:RHEL-193045)
• powerpc/pseries: lparcfg - fix kbuf[] underflow (JIRA:RHEL-240144)

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 - 2337144 - CVE-2024-57849 kernel: s390/cpum_sf: Handle CPU hotplug remove during sampling
• BZ - 2429603 - CVE-2025-71132 kernel: smc91x: fix broken irq-context in PREEMPT_RT
• BZ - 2482006 - CVE-2026-45970 kernel: bonding: alb: fix UAF in rlb_arp_recv during bond up/down
• BZ - 2492735 - CVE-2026-53185 kernel: zram: fix use-after-free in zram_bvec_write_partial()
• BZ - 2502219 - CVE-2026-63800 kernel: pNFS: Fix use-after-free in pnfs_update_layout()
• BZ - 2502227 - CVE-2026-53397 kernel: nfsd: fix posix_acl leak on SETACL decode failure
• BZ - 2502239 - CVE-2026-53399 kernel: nfsd: release layout stid on setlease failure
• BZ - 2502240 - CVE-2026-53392 kernel: NFSv4/flexfiles: reject zero filehandle version count
• BZ - 2502260 - CVE-2026-53391 kernel: NFSv4/pNFS: reject zero-length r_addr in nfs4_decode_mp_ds_addr
• BZ - 2502421 - CVE-2026-64018 kernel: net: mana: validate rx_req_idx to prevent out-of-bounds array access
• BZ - 2507089 - CVE-2026-64268 kernel: Kernel: Remote out-of-bounds write in RDMA/siw
• BZ - 2507208 - CVE-2026-64298 kernel: NFSv4: include MAY_WRITE in open permission mask for O_TRUNC
• BZ - 2508363 - CVE-2026-68480 kernel: AMD-SN-7061: Safe RET Interrupt Vulnerability
• BZ - 2520980 - CVE-2026-74581 kernel: net: ipv6: use-after-free in fib6_rule_suppress due to stale res->rt6 pointer

CVEs

• CVE-2024-57849
• CVE-2025-71132
• CVE-2026-45970
• CVE-2026-53185
• CVE-2026-53391
• CVE-2026-53392
• CVE-2026-53397
• CVE-2026-53399
• CVE-2026-63800
• CVE-2026-64018
• CVE-2026-64268
• CVE-2026-64298
• CVE-2026-68480
• CVE-2026-74581

References

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