CVE-2026-99109 smb: client: reject SetEA requests that do not fit the request buffer

The Linux kernel contains a slab-out-of-bounds vulnerability in the SMB client component. The CIFSSMBSetEA() function fails to verify that the caller's extended attribute value fits within the negotiated SMB request buffer before performing a memcpy. Specifically, the check in cifs_xattr_set() us...