A race condition exists in the Linux kernel SMB client when bit‑field flags in the cifsFileInfo structure are set by distinct code paths protected by separate locks. Because these bit‑field assignments compile to byte‑level read‑modify‑write operations, a concurrent update can overwrite another flag. As a result, state fields such as invalidHandle, swapfile, oplock_break_cancelled, offload, or status_file_deleted may reflect incorrect values, potentially causing wrong file deletion handling, broken opportunistic locking, or improper swapfile management. The flaw does not provide direct code‑execution or data‑leak paths, but it can corrupt SMB file handling behaviour.

The issue can affect any Linux kernel that implements the SMB client, including current mainstream distributions, prior to the application of the bit‑field split fix. No specific version range is supplied, so any kernel before the patch is vulnerable. The patch replaces the shared byte containing several flags with individual boolean members of cifsFileInfo.

The vulnerability is a subtle data‑race; the CVSS score is 4.7 and the EPSS score is < 1%, and it is not in the CISA KEV database. Exploitation would require an attacker to trigger concurrent SMB operations that manipulate the same file structure, which is non‑trivial and has no known public exploits. The practical risk is a disruption of SMB functionality rather than privilege escalation, data loss, or confidentiality breach.