CVE-2026-23230: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Linux Linux Kernel: from 6.1, before 6.1.164 (fixed in 6.1.164); from 6.2, before 6.6.125 (fixed in 6.6.125); from 6.7, before 6.12.72 (fixed in 6.12.72); from 6.13, before 6.18.11 (fixed in 6.18.11); from 6.19, before 6.19.1 (fixed in 6.19.1)

Published 2026-02-18. Last modified 2026-06-17.