RHSA-2026:89082HighCVSS 8.8

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

Published
October 24, 2026
Last Modified
October 26, 2026

🔗 CVE IDs covered (14)

CVE-2026-68140 →CVE-2026-68476 →CVE-2026-72242 →CVE-2026-80824 →CVE-2026-53236 →CVE-2026-68338 →CVE-2026-80586 →CVE-2026-81003 →CVE-2026-89638 →CVE-2026-99999 →CVE-2026-53388 →CVE-2026-64378 →CVE-2026-68136 →CVE-2026-68138 →

📋 Description

CVE-2026-53236 — kernel: tcp: restrict SO_ATTACH_FILTER to priv users CVE-2026-53388 — kernel: fuse: re-lock request before replacing page cache folio CVE-2026-64378 — kernel: writeback: fix race between cgroup_writeback_umount() and inode_switch_wbs() CVE-2026-68136 — kernel: net: gro: fix double aggregation of flush-marked skbs CVE-2026-68138 — kernel: net/sched: serialize qdisc_rtab_list against concurrent get/put CVE-2026-68140 — kernel: net/iucv: fix use-after-free of a severed iucv_path CVE-2026-68338 — kernel: net/packet: avoid fanout hook re-registration after unregister CVE-2026-68476 — kernel: ipvs: reload ip header after head reallocation CVE-2026-72242 — kernel: selinux: avoid sk_socket dereference in selinux_sctp_bind_connect() CVE-2026-80586 — kernel: mptcp: options: reset DSS fields in case of unexpected size CVE-2026-80824 — kernel: usb: usbfs: fix use-after-free of usb_device in usbdev_release() CVE-2026-81003 — kernel: net/iucv: filter frames in afiucv_hs_rcv() by ingress device CVE-2026-89638 — kernel: smb: client: clear setuid/setgid bit on write with cifsacl/modefromsid/posix extensions CVE-2026-99999 — kernel: ipv4: validate checksum_start before completing checksum

🎯 Affected products32

  • Red Hat Enterprise Linux NFV (v. 8)
  • Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-0:4.18.0-553.178.1.rt7.519.el8_10.src as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-0:4.18.0-553.178.1.rt7.519.el8_10.src as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-core-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-core-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-core-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-core-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-debuginfo-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-debuginfo-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-devel-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-devel-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-kvm-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-modules-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-modules-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-modules-extra-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-modules-extra-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debuginfo-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debuginfo-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debuginfo-common-x86_64-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debuginfo-common-x86_64-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-devel-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-devel-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-kvm-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-modules-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-modules-0:4.18.0-553.178.1.rt7.519.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • +2 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. 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. 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: 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. The upstream Linux kernel community recommends updating to a stable kernel release containing the fix (6.6.148, 6.12.101, 6.18.42, or 7.1.6 depending on the stable series); for Red Hat products, apply the kernel updates provided for the affected product streams. Workaround: The vulnerability affects the Multipath TCP (MPTCP) feature in the Linux kernel. To mitigate this issue, MPTCP can be disabled by preventing the `mptcp` kernel module from loading. To disable the `mptcp` module: 1. Create a new file `/etc/modprobe.d/disable-mptcp.conf` with the following content: `install mptcp /bin/true blacklist mptcp` 2. Regenerate the initramfs to ensure the change takes effect on boot: `sudo dracut -f -v` 3. Reboot the system for the changes to take effect. Disabling MPTCP may impact network performance or functionality for applications that rely on Multipath TCP. Workaround: Mount SMB/CIFS shares with the `nosuid` mount option to prevent setuid and setgid binaries from executing with elevated permissions, or prevent the `cifs` module from loading if network SMB shares are not needed. 1. Apply `nosuid` to an active mount point: ``` mount -o remount,nosuid /path/to/cifs/mount ``` 2. Persist this setting by ensuring `nosuid` is present in the mount options within `/etc/fstab`: ``` //server/share /mnt/cifs cifs credentials=/etc/samba/creds,nosuid 0 0 ``` 3. Alternatively, if CIFS mounts are not required on the system, disable autoloading of the kernel module: ``` echo "install cifs /bin/true" > /etc/modprobe.d/cifs.conf ``` Caveats: Enforcing `nosuid` prevents any executable located on the mount point from running with elevated setuid or setgid privileges. Blacklisting the `cifs` module prevents all SMB/CIFS network file systems from mounting. Remounting filesystems can disrupt ongoing read and write operations.

🔗 References (17)