RHSA-2026:26535CriticalCVSS 8.8

Red Hat Security Advisory: kernel security, bug fix, and enhancement update

Published
June 17, 2026
Last Modified
August 4, 2026

🔗 CVE IDs covered (24)

CVE-2026-23001 →CVE-2026-23191 →CVE-2026-23243 →CVE-2026-23392 →CVE-2026-43038 →CVE-2026-43163 →CVE-2026-46243 →CVE-2025-68366 →CVE-2026-31685 →CVE-2023-53372 →CVE-2025-40135 →CVE-2025-40158 →CVE-2025-40170 →CVE-2026-23216 →CVE-2026-43037 →CVE-2026-43110 →CVE-2025-21858 →CVE-2025-68800 →CVE-2025-71089 →CVE-2026-23097 →CVE-2026-43116 →CVE-2026-43158 →CVE-2026-43190 →CVE-2026-46227 →

📋 Description

CVE-2023-53372 — kernel: sctp: fix a potential overflow in sctp_ifwdtsn_skip CVE-2025-21858 — kernel: geneve: Fix use-after-free in geneve_find_dev(). 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-2025-68366 — kernel: nbd: defer config unlock in nbd_genl_connect CVE-2025-68800 — kernel: mlxsw: spectrum_mr: Fix use-after-free when updating multicast route stats CVE-2025-71089 — kernel: iommu: disable SVA when CONFIG_X86 is set CVE-2026-23001 — kernel: macvlan: fix possible UAF in macvlan_forward_source() CVE-2026-23097 — kernel: Linux kernel: Denial of Service due to a deadlock in hugetlb folio migration CVE-2026-23191 — kernel: ALSA: aloop: Fix racy access at PCM trigger CVE-2026-23216 — kernel: scsi: target: iscsi: Fix use-after-free in iscsit_dec_conn_usage_count() CVE-2026-23243 — kernel: Linux kernel: Denial of service and memory corruption in RDMA umad 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-2026-43037 — 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 CVE-2026-43116 — kernel: netfilter: ctnetlink: ensure safe access to master conntrack CVE-2026-43158 — kernel: xfs: fix freemap adjustments when adding xattrs to leaf blocks CVE-2026-43163 — kernel: md/bitmap: fix GPF in write_page caused by resize race CVE-2026-43190 — kernel: netfilter: xt_tcpmss: check remaining length before reading optlen CVE-2026-46227 — kernel: sctp: revalidate list cursor after sctp_sendmsg_to_asoc() in SCTP_SENDALL CVE-2026-46243 — kernel: Linux kernel: smb: client: reject userspace cifs.spnego descriptions

🎯 Affected products52

  • Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • bpftool-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • bpftool-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • bpftool-debuginfo-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • bpftool-debuginfo-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • kernel-0:4.18.0-305.194.1.el8_4.src as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • kernel-0:4.18.0-305.194.1.el8_4.src as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • kernel-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • kernel-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • kernel-abi-stablelists-0:4.18.0-305.194.1.el8_4.noarch as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • kernel-abi-stablelists-0:4.18.0-305.194.1.el8_4.noarch as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • kernel-core-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • kernel-core-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • kernel-debug-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • kernel-debug-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • kernel-debug-core-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • kernel-debug-core-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • kernel-debug-debuginfo-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • kernel-debug-debuginfo-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • kernel-debug-devel-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • kernel-debug-devel-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • kernel-debug-modules-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • kernel-debug-modules-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • kernel-debug-modules-extra-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • kernel-debug-modules-extra-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • kernel-debuginfo-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • kernel-debuginfo-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • kernel-debuginfo-common-x86_64-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS AUS (v.8.4)
  • kernel-debuginfo-common-x86_64-0:4.18.0-305.194.1.el8_4.x86_64 as a component of Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4)
  • +22 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 module macvlan from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically. 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 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, prevent module ib_umad from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically. 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: 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. Workaround: Mitigation for this issue is to skip loading the affected module "netfilter" 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 ~~~ Workaround: To mitigate this issue, prevent module sctp from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically. Workaround: See the security bulletin for a detailed mitigation procedure.

🔗 References (27)