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...

CVE-2026-64398

In the Linux kernel, the following vulnerability has been resolved: ksmbd: add a permission check for FSCTLSETZERODATA FSCTLSETZERODATA in smb2ioctl destroys file data via ksmbdvfszerodata - vfsfallocatePUNCHHOLE/ZERORANGE after checking only the share-level KSMBDTREECONNFLAGWRITABLE, with no...