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CVE-2026-98686

Linux: smb: client: discard post-EOF pagecache when extending a file via zero 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 in3df27277f8f95345d4a6c57367824bf1aefdbf66Also 94949b6b2f2bf0dba2e8786aed0b08cc6bc3a183, 6a8279c98ad289b27c0bdb11adb3f0c0b7fd456dCVE List
Published18 Oct 2026Updated 21 Oct 2026CVE List

What fixes it

  • 3df27277f8f95345d4a6c57367824bf1aefdbf66LinuxCVE List
  • 94949b6b2f2bf0dba2e8786aed0b08cc6bc3a183LinuxCVE List
  • 6a8279c98ad289b27c0bdb11adb3f0c0b7fd456dLinuxCVE List

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: discard post-EOF pagecache when extending a file via zero range

smb3_zero_range() removed the pagecache only for the range being zeroed, so when it extends the file the folio straddling the old EOF - which may hold data dirtied past EOF through an mmap - was never dropped and became visible as file content once the file was extended.

Lower the discard boundary to the smaller of the zero-range offset and the old EOF.

Text from CVE List

Affected versions 12

  • Linuxaffected: 72c419d9b073628d3b5b0b2fc787b724f1a8c726 before 3df27277f8f95345d4a6c57367824bf1aefdbf66CVE List
  • Linuxaffected: 72c419d9b073628d3b5b0b2fc787b724f1a8c726 before 94949b6b2f2bf0dba2e8786aed0b08cc6bc3a183CVE List
  • Linuxaffected: 72c419d9b073628d3b5b0b2fc787b724f1a8c726 before b75dadb50a25eed525264bf6fea44fad94e7626fCVE List
  • Linuxaffected: 72c419d9b073628d3b5b0b2fc787b724f1a8c726 before 6a8279c98ad289b27c0bdb11adb3f0c0b7fd456dCVE List
  • Linuxaffected: 72c419d9b073628d3b5b0b2fc787b724f1a8c726 before da4fe97fb6c730d9c94a115c7bfa6f98e0d578d0CVE List
  • Linuxaffected: 5.1CVE List
  • Linuxunaffected: all versions before 5.1CVE List
  • Linuxunaffected: 6.6.160 through 6.6.*CVE List
  • Linuxunaffected: 6.12.113 through 6.12.*CVE List
  • Linuxunaffected: 6.18.56 through 6.18.*CVE List
  • Linuxunaffected: 7.2.10 through 7.2.*CVE List
  • Linuxunaffected: 7.3CVE List

References 5