CVE-2026-46243 is a vulnerability in the Linux kernel-rt SMB client component that improperly handles userspace cifs.spnego descriptions. This vulnerability affects Red Hat Enterprise Linux 8 Real Time kernel packages and related variants. Red Hat has issued an important security advisory (RHSA-2026:23259) providing updated kernel-rt packages that address this issue. The update requires a system reboot to activate the fix. The advisory references the CVE for detailed impact and scoring information, but no CVSS score is provided in the advisory or CVE data. No exploits are currently known in the wild.

The vulnerability could potentially allow improper handling of SMB client authentication descriptions, which may affect system security in environments using the Real Time Linux Kernel. The exact impact details and exploitability are not provided, but Red Hat rates the update as important, indicating a significant security concern. There are no known exploits in the wild at this time.

Red Hat has released updated kernel-rt packages that fix this vulnerability. Users of affected Red Hat Enterprise Linux 8 Real Time kernel packages should apply the security update as described in Red Hat advisory RHSA-2026:23259. After applying the update, a system reboot is required for the fix to take effect. There is no indication from the vendor advisory that additional mitigation steps are necessary.