CVE-2026-90176

In the Linux kernel, the following vulnerability has been resolved: ksmbd: Do not skip lock checks for single-byte ranges check_lock_range() uses inclusive ranges. Its callers pass the end offset as start + length - 1, so start == end represents a valid single-byte range rather than an empty range. The start == end shortcut therefore skips mandatory byte-range lock checks for one-byte reads, writes, copychunk operations and one-byte truncate ranges. A conflicting lock covering that byte is not checked and the operation is allowed to proceed. Remove the shortcut. The truncate size == inode->i_size case is already handled by only calling check_lock_range() when the new size differs from the current file size.

• https://git.kernel.org/stable/c/07a9e289ff7edcc004f58952405f8a65c4e37512
• https://git.kernel.org/stable/c/84c2d8e807ac489f5c91769293fb15dfdae8bae8
• https://git.kernel.org/stable/c/993e0158331d37c04da18efe551b5e1e35fb3078
• https://git.kernel.org/stable/c/a89cc145832e81c32199d4ca2e1ea8bd51ed601d
• https://git.kernel.org/stable/c/d40c24634fe077a0dc91fd11fccf44ce12b454d5
• https://git.kernel.org/stable/c/f751d6e39d4c937c45f8fedc66699aa7d2d52288