CVE-2026-23230

In the Linux kernel, the following vulnerability has been resolved:

smb: client: split cached_fid bitfields to avoid shared-byte RMW races

is_open, has_lease and on_list are stored in the same bitfield byte in

struct cached_fid but are updated in different code paths that may run

concurrently. Bitfield assignments generate byte read–modify–write

operations (e.g. `orb $mask, addr` on x86_64), so updating one flag can

restore stale values of the others.

A possible interleaving is:

CPU1: load old byte (has_lease=1, on_list=1)

CPU2: clear both flags (store 0)

CPU1: RMW store (old | IS_OPEN) -> reintroduces cleared bits

To avoid this class of races, convert these flags to separate bool

fields.