---
id: "CVE-2026-98681"
kind: "vulnerability"
aliases: ["CVE-2026-98681"]
title: "Linux kernel SMB client: shared bitfield flags race and corrupt state"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["cifs", "linux-kernel", "other", "smb-client"]
not_affected_if: []
published_at: "2026-10-18T16:17:21+00:00"
first_seen_at: "2026-10-23T21:57:16+00:00"
updated_at: "2026-10-25T05:19:13+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98681", "first_seen_at": "2026-10-23T21:57:16+00:00"}]
---

# Linux kernel SMB client: shared bitfield flags race and corrupt state

In the Linux kernel's CIFS/SMB client, several flags in struct cifsFileInfo share one bitfield byte but are updated under different locks, so concurrent writes can overwrite each other. The sources describe a memory-corruption-style race in kernel state but do not state a concrete attacker outcome.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- unknown

## Fix

- unknown

## Timeline

- 2026-10-23T21:57:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98681

## From the sources

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

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

The invalidHandle, swapfile, oplock_break_cancelled, offload,
and status_file_deleted fields are stored in the same bitfield byte
in struct cifsFileInfo, but are updated in different code paths that
may run simultaneously, and are protected by different locks.  Since
bitfield assignments generate byte-level read-modify-write operations,
a modification to one flag can overwrite a concurrent modification to
another flag.

To avoid these races, convert these flags from a bitfield to
separate bool fields.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_