CVE-2026-98683
Received Received - Intake

Linux kernel SMB client zero range data corruption

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: flush dirty data before zeroing a range smb3_zero_range() emulates FALLOC_FL_ZERO_RANGE by invalidating the page cache over the target range with truncate_pagecache_range() and then issuing FSCTL_SET_ZERO_DATA to the server. Dirty data was only flushed conditionally, when the range reached or extended EOF. For a purely interior zero range that does not reach EOF, no flush happened, so a dirty folio overlapping the range could be written back to the server after the FSCTL and refill the range that was just zeroed with stale data. Fix this by unconditionally flushing and waiting for dirty data in the range before invalidating the page cache and issuing FSCTL_SET_ZERO_DATA, exactly as was done for smb3_punch_hole() in commit d7d2adcd022b ("smb/client: flush dirty data before punching a hole"); the two paths are structurally identical here. This is observed as generic/363 randomly reading stale data where a zeroed range is expected against Windows Server.

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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-2026-98683
EUVD
EUVD-2026-103937

Affected Vendors & Products

Showing 10 associated CPEs
Vendor Product Version / Range
Linux Linux 91d1dfae464987aaf6c79ff51d8674880fb3be77
Linux Linux 91d1dfae464987aaf6c79ff51d8674880fb3be77
Linux Linux 91d1dfae464987aaf6c79ff51d8674880fb3be77
Linux Linux 13af7446428771e9e529284d390e7994df8be683
Linux Linux 0a9423f99ded38b32bd1864347332cc557e6b141
Linux Linux 7dfa4279c55f467a88e653a5d544817181b22aea
Linux Linux 6.1.110
Linux Linux 6.6.51
Linux Linux 6.10.10
Linux Linux 6.11

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves the smb3_zero_range function, which is used to zero out a file range. The issue occurs because dirty data (data that has been modified but not yet written to disk) is not always flushed before zeroing the range. This can lead to stale data being written back to the server after the zero operation, causing data inconsistency.

Detection Guidance

This vulnerability is specific to the Linux kernel's SMB client implementation and may not have direct detection commands. It involves stale data reads in zeroed ranges, which could be observed in filesystem tests like generic/363. Check kernel logs for SMB-related errors or filesystem inconsistencies after SMB operations.

Impact Analysis

If exploited, this vulnerability could result in reading stale or incorrect data from a file after a zero operation. This might lead to data corruption, unexpected behavior in applications relying on file data, or security issues if sensitive data is involved. Users may experience data inconsistencies or errors when working with files over SMB shares.

Mitigation Strategies

Update the Linux kernel to a patched version that includes the fix for smb3_zero_range(). The patch ensures dirty data is flushed before zeroing ranges, preventing stale data issues. Monitor vendor advisories for kernel updates addressing this CVE.

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