Stale-data disclosure via unzeroed CIFS page tail
Published Sep 11, 2026 · Updated Sep 11, 2026
Information disclosure in the Linux CIFS client before 7.2.4 allows local users to expose stale page-cache data through file extension. cifs_setsize() updates i_size and truncates the page cache without calling pagecache_isize_extended() when a file grows, leaving dirty bytes beyond the old EOF intact. Local users must have permission to extend a file on a mounted CIFS share; stale bytes can then be written back into the new server-side range.
Summary
What happened
Information disclosure in the Linux CIFS client before 7.2.4 allows local users to expose stale page-cache data through file extension. cifs_setsize() updates i_size and truncates the page cache without calling pagecache_isize_extended() when a file grows, leaving dirty bytes beyond the old EOF intact. Local users must have permission to extend a file on a mounted CIFS share; stale bytes can then be written back into the new server-side range.
The record
- CVE
- CVE-2026-89642
- Published
- Sep 11, 2026
- Updated
- Sep 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1005
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 11, 2026CVE publishedPublication date reported by the CVE source.
- Sep 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <7.2.4
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <12bafe32f09c0d24f5096154b59c347b9c6606e0
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c510edb9734af1c274d18f4f31a471a166bbc7e8
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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