RHSA-2026:22900 - Security Advisory

Topic

An update for kernel-rt is now available for Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions.

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: net/sched: Make cake_enqueue return NET_XMIT_CN when past buffer_limit (CVE-2025-39766)
• kernel: Linux kernel: Use-after-free in traffic control (act_ct) may lead to denial of service or privilege escalation (CVE-2026-23270)
• kernel: Linux kernel: Use-after-free in bonding driver leads to denial of service (CVE-2026-31419)
• kernel: ip6_tunnel: clear skb2->cb[] in ip4ip6_err() (CVE-2026-43037)
• kernel: ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach() (CVE-2026-43038)
• kernel: smb: client: validate the whole DACL before rewriting it in cifsacl (CVE-2026-31709)
• kernel: md/bitmap: fix GPF in write_page caused by resize race (CVE-2026-43163)

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.

Affected Products

• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 9.2 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 9.2 x86_64

Fixes

• BZ - 2394648 - CVE-2025-39766 kernel: net/sched: Make cake_enqueue return NET_XMIT_CN when past buffer_limit
• BZ - 2448745 - CVE-2026-23270 kernel: Linux kernel: Use-after-free in traffic control (act_ct) may lead to denial of service or privilege escalation
• BZ - 2457829 - CVE-2026-31419 kernel: Linux kernel: Use-after-free in bonding driver leads to denial of service
• BZ - 2464351 - CVE-2026-43037 kernel: ip6_tunnel: clear skb2->cb[] in ip4ip6_err()
• BZ - 2464397 - CVE-2026-43038 kernel: ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()
• BZ - 2464476 - CVE-2026-31709 kernel: smb: client: validate the whole DACL before rewriting it in cifsacl
• BZ - 2467059 - CVE-2026-43163 kernel: md/bitmap: fix GPF in write_page caused by resize race

CVEs

• CVE-2025-39766
• CVE-2026-23270
• CVE-2026-31419
• CVE-2026-31709
• CVE-2026-43037
• CVE-2026-43038
• CVE-2026-43163

References

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