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CVE-2026-98683

Linux: smb: client: flush dirty data before zeroing a range

Linux LinuxOperating systems
Open in ThreatlineRecord JSON
CVSS
NoneNot scored
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.17%Chance of exploitation activity in the next 30 days, higher than 5% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in8f8d32c1044f70e46e87550e039a15ff20a4b21cAlso 6.2, 6.7 and 1 moreCVE List
Published18 Oct 2026Updated 19 Oct 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 14

  • Linuxaffected: 91d1dfae464987aaf6c79ff51d8674880fb3be77 before cecf4114069fc19629d284710fd783d56bbca862CVE List
  • Linuxaffected: 91d1dfae464987aaf6c79ff51d8674880fb3be77 before e8ba21c7e6ef3d4cb617858760673877b2e4a2bbCVE List
  • Linuxaffected: 91d1dfae464987aaf6c79ff51d8674880fb3be77 before 8f8d32c1044f70e46e87550e039a15ff20a4b21cCVE List
  • Linuxaffected: 13af7446428771e9e529284d390e7994df8be683CVE List
  • Linuxaffected: 0a9423f99ded38b32bd1864347332cc557e6b141CVE List
  • Linuxaffected: 7dfa4279c55f467a88e653a5d544817181b22aeaCVE List
  • Linuxaffected: 6.1.110 before 6.2CVE List
  • Linuxaffected: 6.6.51 before 6.7CVE List
  • Linuxaffected: 6.10.10 before 6.11CVE List
  • Linuxaffected: 6.11CVE List
  • Linuxunaffected: all versions before 6.11CVE List
  • Linuxunaffected: 6.18.56 through 6.18.*CVE List
  • Linuxunaffected: 7.2.10 through 7.2.*CVE List
  • Linuxunaffected: 7.3CVE List

References 3