Linux Kernel CVE-2026-43239

Upgrade to patched Linux kernel versions: 6.6.128 or later for 6.6.x branch, 6.12.75+ for 6.12.x, 6.18.16+ for 6.18.x, 6.19.6+ for 6.19.x, or 7.0+ for mainline. Kernel patches available from https://git.kernel.org/stable/ with commit IDs 93e8e3ee165a, ab6564f416a6, 6287eefaf21e, 76cc4faba034, and c3c06e42e152 for various branches. Distribution-specific packages should be obtained through official channels (apt/yum/dnf update). For systems unable to immediately patch, temporary risk reduction can be achieved by restricting SMB client usage to trusted networks only through firewall rules blocking outbound ports 445/TCP and 139/TCP to untrusted destinations, though this significantly limits SMB functionality. Another mitigation is disabling automatic SMB interface negotiation by avoiding concurrent mount operations, but this is operationally impractical and does not eliminate the vulnerability. These workarounds provide minimal protection and should not replace patching. No significant side effects expected from kernel updates within the same stable branch series. Reboot required to activate patched kernel.