Linux Kernel ksmbd EUVD-2026-28683

Upgrade to patched Linux kernel versions: 6.1.167, 6.6.130, 6.12.78, 6.18.20, 6.19.9, or 7.0 depending on your stable branch. Patches are available from https://git.kernel.org/stable/ with specific commits listed in the references. For systems where immediate patching is not feasible, disable KSMBD_DEBUG_AUTH debug logging if currently enabled by removing or commenting the debug flag from ksmbd configuration and restarting the ksmbd service. This eliminates the vulnerability but may complicate troubleshooting of ksmbd issues. As a defense-in-depth measure, restrict access to kernel logs (dmesg output and /var/log/kern.log) using filesystem permissions and log aggregation access controls to limit exposure even if keys are logged. Note that restricting log access does not fix the underlying issue but reduces attack surface; this trade-off may impact security monitoring and incident response capabilities. Audit existing kernel logs for exposed key material from past sessions when debug mode was enabled and consider rotating SMB credentials if exposure is confirmed.