CVE-2026-98683

/// Technical 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 wher

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References