CVE-2026-98681
Received Received - Intake

smb: client: Race Condition in cifsFileInfo Bitfields

Publication date: 2026-10-18

Last updated on: 2026-10-18

Assigner: kernel.org

Description
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.

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Meta Information

Published
2026-10-18
Last Modified
2026-10-18
Generated
2026-10-18
AI Q&A
2026-10-18
EPSS Evaluated
N/A
NVD
CVE-2026-98681
EUVD
EUVD-2026-103935

Affected Vendors & Products

Showing 5 associated CPEs
Vendor Product Version / Range
Linux Linux 3bc303c254335dbd7c7012cc1760b12f1d5514d3
Linux Linux 3bc303c254335dbd7c7012cc1760b12f1d5514d3
Linux Linux 3bc303c254335dbd7c7012cc1760b12f1d5514d3
Linux Linux 3bc303c254335dbd7c7012cc1760b12f1d5514d3
Linux Linux 2.6.32

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a race condition in the Linux kernel's SMB client implementation. It involves bitfields in the cifsFileInfo structure that are updated by different code paths under separate locks. Since bitfield changes use read-modify-write operations, modifying one flag can unintentionally overwrite another flag being changed simultaneously.

Detection Guidance

This vulnerability is specific to the Linux kernel's CIFS client implementation and involves race conditions in bitfield operations. Detection requires checking the kernel version and examining the cifsFileInfo structure in the kernel source code. No direct commands can detect this without access to kernel source or debugging tools.

Impact Analysis

This could lead to data corruption or unexpected behavior in SMB client operations. If exploited, it might cause file access issues, incorrect file status handling, or crashes in applications using the SMB protocol.

Mitigation Strategies

Update your Linux kernel to the latest stable version where this issue has been resolved. If an update is not immediately available, avoid using the CIFS client for critical operations until patched. Monitor vendor advisories for kernel updates addressing this CVE.

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