UBUNTU-CVE-2026-64399

In the Linux kernel, the following vulnerability has been resolved: ksmbd: add permission checks for FSCTLDUPLICATEEXTENTSTOFILE The FSCTLDUPLICATEEXTENTSTOFILE arm of smb2ioctl overwrites the destination file's data via vfsclonefilerange with neither the share-level KSMBDTREECONNFLAGWRITABLE che...

CVE-2026-64398

CVE-2026-64398 affects the Linux kernel ksmbd component. A permission check bypass in FSCTL_SET_ZERO_DATA allows an authenticated SMB client with only FILE_WRITE_ATTRIBUTES to zero out file data via fsctl path, bypassing per-handle checks. The operation uses vfs_fallocate(PUNCH_HOLE/ZERO_RANGE) a...