The Red Hat kernel-rt packages, which provide a Real Time Linux Kernel for systems requiring high determinism, have received a security update addressing four vulnerabilities: CVE-2026-31684 fixes validation of nested VLAN headers in the network scheduler checksum action; CVE-2026-43499 corrects the use of waiter::task instead of the current task in remove_waiter() within rtmutex; CVE-2026-46116 adds defensive unhashing of xfrm_state lists in __xfrm_state_delete; and CVE-2026-53166 prevents a NULL pointer dereference in remove_waiter() during futex requeue on self-deadlock. These fixes are included in an update for Red Hat Enterprise Linux 7 Extended Lifecycle Support kernel-rt packages. The advisory rates the security impact as Important (high) and requires a system reboot after patching.

The vulnerabilities affect the kernel-rt packages used in Red Hat Enterprise Linux 7 Extended Lifecycle Support. They could lead to kernel instability or crashes due to improper handling of VLAN headers, mutex waiter tasks, xfrm_state list unhashing, and futex requeue operations. While no known exploits in the wild are reported, these issues pose a risk to system reliability and security in real-time kernel environments.

An official security update is available from Red Hat for the kernel-rt packages addressing these vulnerabilities. Users should apply the update as detailed in the Red Hat advisory RHSA-2026:41234 and reboot their systems to ensure the fixes take effect. No additional mitigation steps are indicated by the vendor.