RHSA-2026:23237HighCVSS 8.8

Red Hat Security Advisory: kernel security update

Published
June 4, 2026
Last Modified
August 21, 2026

🔗 CVE IDs covered (12)

CVE-2026-23392 →CVE-2026-31685 →CVE-2026-43037 →CVE-2025-68724 →CVE-2026-31709 →CVE-2026-43038 →CVE-2026-43110 →CVE-2025-40135 →CVE-2025-40158 →CVE-2025-40170 →CVE-2025-71089 →CVE-2026-23216 →

📋 Description

CVE-2025-40135 — kernel: ipv6: use RCU in ip6_xmit() CVE-2025-40158 — kernel: ipv6: use RCU in ip6_output() CVE-2025-40170 — kernel: net: use dst_dev_rcu() in sk_setup_caps() CVE-2025-68724 — kernel: crypto: asymmetric_keys - prevent overflow in asymmetric_key_generate_id CVE-2025-71089 — kernel: iommu: disable SVA when CONFIG_X86 is set CVE-2026-23216 — kernel: scsi: target: iscsi: Fix use-after-free in iscsit_dec_conn_usage_count() CVE-2026-23392 — kernel: netfilter: nf_tables: release flowtable after rcu grace period on error CVE-2026-31685 — kernel: netfilter: ip6t_eui64: reject invalid MAC header for all packets CVE-2026-31709 — kernel: smb: client: validate the whole DACL before rewriting it in cifsacl CVE-2026-43037 — kernel: ip6_tunnel: clear skb2->cb[] in ip4ip6_err() CVE-2026-43038 — kernel: ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach() CVE-2026-43110 — kernel: wifi: brcmfmac: validate bsscfg indices in IF events

🎯 Affected products200

  • Red Hat Enterprise Linux AppStream E4S (v.9.4)
  • Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • Red Hat Enterprise Linux Real Time E4S (v.9.4)
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4)
  • bpftool-0:7.3.0-427.129.1.el9_4.aarch64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • bpftool-0:7.3.0-427.129.1.el9_4.ppc64le as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • bpftool-0:7.3.0-427.129.1.el9_4.s390x as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • bpftool-0:7.3.0-427.129.1.el9_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • bpftool-debuginfo-0:7.3.0-427.129.1.el9_4.aarch64 as a component of Red Hat Enterprise Linux AppStream E4S (v.9.4)
  • bpftool-debuginfo-0:7.3.0-427.129.1.el9_4.aarch64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • bpftool-debuginfo-0:7.3.0-427.129.1.el9_4.ppc64le as a component of Red Hat Enterprise Linux AppStream E4S (v.9.4)
  • bpftool-debuginfo-0:7.3.0-427.129.1.el9_4.ppc64le as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • bpftool-debuginfo-0:7.3.0-427.129.1.el9_4.s390x as a component of Red Hat Enterprise Linux AppStream E4S (v.9.4)
  • bpftool-debuginfo-0:7.3.0-427.129.1.el9_4.s390x as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • bpftool-debuginfo-0:7.3.0-427.129.1.el9_4.x86_64 as a component of Red Hat Enterprise Linux AppStream E4S (v.9.4)
  • bpftool-debuginfo-0:7.3.0-427.129.1.el9_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • bpftool-debuginfo-0:7.3.0-427.129.1.el9_4.x86_64 as a component of Red Hat Enterprise Linux Real Time E4S (v.9.4)
  • bpftool-debuginfo-0:7.3.0-427.129.1.el9_4.x86_64 as a component of Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4)
  • kernel-0:5.14.0-427.129.1.el9_4.aarch64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • kernel-0:5.14.0-427.129.1.el9_4.ppc64le as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • kernel-0:5.14.0-427.129.1.el9_4.s390x as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • kernel-0:5.14.0-427.129.1.el9_4.src as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • kernel-0:5.14.0-427.129.1.el9_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • kernel-64k-0:5.14.0-427.129.1.el9_4.aarch64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • kernel-64k-core-0:5.14.0-427.129.1.el9_4.aarch64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • kernel-64k-debug-0:5.14.0-427.129.1.el9_4.aarch64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • kernel-64k-debug-core-0:5.14.0-427.129.1.el9_4.aarch64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • kernel-64k-debug-debuginfo-0:5.14.0-427.129.1.el9_4.aarch64 as a component of Red Hat Enterprise Linux AppStream E4S (v.9.4)
  • kernel-64k-debug-debuginfo-0:5.14.0-427.129.1.el9_4.aarch64 as a component of Red Hat Enterprise Linux BaseOS E4S (v.9.4)
  • kernel-64k-debug-devel-0:5.14.0-427.129.1.el9_4.aarch64 as a component of Red Hat Enterprise Linux AppStream E4S (v.9.4)
  • +170 more not shown

✅ Remediation

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. Workaround: Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Workaround: To mitigate this issue, prevent the iscsi_target_mod module from being loaded. See https://access.redhat.com/solutions/41278 for instructions on how to blacklist kernel modules. Workaround: To mitigate this issue, if SMB client functionality is not required, the `cifs` kernel module can be blacklisted to prevent it from loading. This can be achieved by creating a modprobe configuration file. 1. Create a file named `/etc/modprobe.d/disable-cifs.conf` with the following content: ``` install cifs /bin/true blacklist cifs ``` 2. Regenerate the initramfs to ensure the change takes effect on boot: ```bash dracut -f -v ``` or for systems using `mkinitrd`: ```bash mkinitrd -f /boot/initramfs-$(uname -r).img $(uname -r) ``` 3. A system reboot is required for the changes to take effect. Warning: Disabling the `cifs` module will prevent the system from mounting SMB/CIFS shares. Ensure this functionality is not critical before applying this mitigation. refer: https://access.redhat.com/solutions/4117281 Workaround: Mitigation for this issue is to skip loading the affected module `ip6_tunnel` onto the system till we have a fix available, this can be done by a blacklist mechanism, this will ensure the driver is not loaded at the boot time. ~~~ How do I blacklist a kernel module to prevent it from loading automatically? https://access.redhat.com/solutions/41278 ~~~ We may also want to detection and monitoring an affected system as below: ~~~ Monitor for exploitation attempts: # Enable kernel audit for IPv6 tunnel operations auditctl -a always,exit -F arch=b64 -S socket -F a0=10 -F a1=3 -k ipv6_tunnel # Monitor system logs for kernel panics/crashes journalctl -k -p err -f | grep -i "ip6_tunnel\|icmp\|stack" ~~~ Workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. Workaround: To mitigate this issue, prevent module brcmfmac from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.

🔗 References (15)