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.

• linux linux kernel (>= 6.1 < 6.1.164) • linux linux kernel (>= 6.2 < 6.6.125) • linux linux kernel (>= 6.7 < 6.12.72) • linux linux kernel (>= 6.13 < 6.18.11) • linux linux kernel (>= 6.19 < 6.19.1)