Bug 2532207 (CVE-2026-89642) - CVE-2026-89642 kernel: Linux kernel: CIFS information disclosure via stale data exposure during file extension
Summary: CVE-2026-89642 kernel: Linux kernel: CIFS information disclosure via stale da...
Keywords:
Status: NEW
Alias: CVE-2026-89642
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-11 21:21 UTC by OSIDB Bzimport
Modified: 2026-09-15 04:48 UTC (History)
15 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-09-11 21:21:29 UTC
In the Linux kernel, the following vulnerability has been resolved:

cifs: call pagecache_isize_extended() in cifs_setsize() when extending

cifs_setsize() calls truncate_pagecache() but skips
pagecache_isize_extended() on extension.  truncate_setsize() shows
the correct pattern:

  i_size_write(inode, newsize);
  if (newsize > oldsize)
      pagecache_isize_extended(inode, oldsize, newsize);
  truncate_pagecache(inode, newsize);

pagecache_isize_extended() zeroes the tail of the page straddling old
EOF.  Without it, dirty bytes in that region can be written back to
the server, exposing stale data in the newly extended range.


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