RHSA-2026:21745HighCVSS 7.8

Red Hat Security Advisory: kernel-rt security update

Published
May 28, 2026
Last Modified
September 11, 2026

🔗 CVE IDs covered (19)

CVE-2026-31685 →CVE-2026-31709 →CVE-2026-43020 →CVE-2026-43027 →CVE-2026-43051 →CVE-2026-43158 →CVE-2026-23270 →CVE-2026-23455 →CVE-2026-43163 →CVE-2026-46195 →CVE-2025-39981 →CVE-2025-68183 →CVE-2025-71116 →CVE-2026-31408 →CVE-2026-43190 →CVE-2025-68347 →CVE-2026-31532 →CVE-2026-23243 →CVE-2026-31684 →

📋 Description

CVE-2025-39981 — kernel: Bluetooth: MGMT: Fix possible UAFs CVE-2025-68183 — kernel: ima: don't clear IMA_DIGSIG flag when setting or removing non-IMA xattr CVE-2025-68347 — kernel: ALSA: firewire-motu: fix buffer overflow in hwdep read for DSP events CVE-2025-71116 — kernel: libceph: make decode_pool() more resilient against corrupted osdmaps CVE-2026-23243 — kernel: Linux kernel: Denial of service and memory corruption in RDMA umad CVE-2026-23270 — kernel: Linux kernel: Use-after-free in traffic control (act_ct) may lead to denial of service or privilege escalation CVE-2026-23455 — kernel: netfilter: nf_conntrack_h323: check for zero length in DecodeQ931() CVE-2026-31408 — kernel: Bluetooth: SCO: Fix use-after-free in sco_recv_frame() due to missing sock_hold CVE-2026-31532 — kernel: can: raw: fix ro->uniq use-after-free in raw_rcv() CVE-2026-31684 — kernel: net: sched: act_csum: validate nested VLAN headers 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-2026-43020 — kernel: Bluetooth: MGMT: validate LTK enc_size on load CVE-2026-43027 — kernel: netfilter: nf_conntrack_helper: pass helper to expect cleanup CVE-2026-43051 — kernel: HID: wacom: fix out-of-bounds read in wacom_intuos_bt_irq 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-2026-46195 — kernel: smb: client: validate dacloffset before building DACL pointers

🎯 Affected products32

  • Red Hat Enterprise Linux NFV (v. 8)
  • Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-0:4.18.0-553.126.1.rt7.467.el8_10.src as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-0:4.18.0-553.126.1.rt7.467.el8_10.src as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-core-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-core-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-core-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-core-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-debuginfo-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-debuginfo-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-devel-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-devel-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-kvm-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-modules-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-modules-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debug-modules-extra-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debug-modules-extra-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debuginfo-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debuginfo-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-debuginfo-common-x86_64-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-debuginfo-common-x86_64-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-devel-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-devel-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux RT (v. 8)
  • kernel-rt-kvm-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-modules-0:4.18.0-553.126.1.rt7.467.el8_10.x86_64 as a component of Red Hat Enterprise Linux NFV (v. 8)
  • kernel-rt-modules-0:4.18.0-553.126.1.rt7.467.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. Workaround: Ensure Bluetooth management interfaces are hardened or, if unused, disabled. Workaround: To mitigate this issue and if Ceph not being used, then prevent module libceph 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: 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: To mitigate this issue, prevent the `can` kernel module from loading if CAN functionality is not required. This can be achieved by blacklisting the module. Create a file named `/etc/modprobe.d/blacklist-can.conf` with the following content: ``` blacklist can install can /bin/true ``` After creating the file, regenerate the initramfs and reboot the system for the changes to take effect. ```bash dracut -f -v reboot ``` This mitigation may impact systems that rely on CAN interfaces for their operation. 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 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, avoid mounting shares from untrusted SMB servers on 32-bit Red Hat Enterprise Linux systems. If interaction with untrusted SMB servers is unavoidable, consider isolating affected systems or restricting network access to only known, trusted SMB servers.

🔗 References (21)