RHSA-2026:93437 - 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: ipv6: exthdrs: refresh nh pointer after ipv6_hop_jumbo() (CVE-2026-63924)
• kernel: ipv6: exthdrs: refresh nh after handling HAO option (CVE-2026-63922)
• kernel: af_unix: Fix UAF read of tail->len in unix_stream_data_wait() (CVE-2026-64109)
• kernel: scsi: target: core: Fix iSCSI ISID use-after-free in REGISTER AND MOVE (CVE-2026-72083)
• kernel: tipc: require net admin for TIPCv2 netlink mutators (CVE-2026-74283)
• kernel: smb: client: bound dirent name against end of SMB response in cifs_filldir (CVE-2026-93787)
• kernel: ZDI-CAN-33367: Linux Kernel skbuff skb_zerocopy Improper Ownership Management Local Privilege Escalation Vulnerability ()

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 - 2502326 - CVE-2026-63924 kernel: ipv6: exthdrs: refresh nh pointer after ipv6_hop_jumbo()
• BZ - 2502327 - CVE-2026-63922 kernel: ipv6: exthdrs: refresh nh after handling HAO option
• BZ - 2502615 - CVE-2026-64109 kernel: af_unix: Fix UAF read of tail->len in unix_stream_data_wait()
• BZ - 2516579 - CVE-2026-72083 kernel: scsi: target: core: Fix iSCSI ISID use-after-free in REGISTER AND MOVE
• BZ - 2516935 - CVE-2026-74283 kernel: tipc: require net admin for TIPCv2 netlink mutators
• BZ - 2540555 - CVE-2026-93787 kernel: smb: client: bound dirent name against end of SMB response in cifs_filldir
• BZ - 2559835 - kernel: ZDI-CAN-33367: Linux Kernel skbuff skb_zerocopy Improper Ownership Management Local Privilege Escalation Vulnerability

CVEs

• CVE-2026-63922
• CVE-2026-63924
• CVE-2026-64109
• CVE-2026-72083
• CVE-2026-74283
• CVE-2026-93787

References

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