CVE-2026-23230

About vulnerability

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. A flaw was found in the Linux kernel’s Server Message Block (SMB) client. This vulnerability is caused by a race condition during concurrent updates to internal flags, which can lead to stale data being restored. A remote attacker with low privileges could exploit this, potentially causing unexpected behavior or a denial of service in the SMB client.

Live-patch status from KernelCare for each operating system.