CVE-2026-99083

A flaw was found in the Linux kernel's ksmbd Server Message Block (SMB) server. When handling compounded SMB requests during Kerberos authentication, the server incorrectly calculates available buffer space, leading to a heap-based out-of-bounds write. A remote attacker could exploit this vulnerability by sending specially crafted requests, potentially allowing arbitrary code execution or causing a system crash that results in a Denial of Service (DoS).

Critical severity is assigned because unauthenticated remote attackers could achieve arbitrary code execution via kernel heap corruption over the network. However, Red Hat Enterprise Linux does not enable or ship the in-kernel SMB server (ksmbd), relying instead on user-space Samba implementations. Because the vulnerable module is not compiled into supported Red Hat kernels, standard product deployments are not affected.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.