Medium [CVE-2026-89642] Linux kernel: CIFS information disclosure via stale data exposure during file extension
This medium-severity Red Hat Linux advisory covers CVE-2026-89642.
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Summary
A flaw was found in the Linux kernel's Common Internet File System (CIFS) implementation. When a client extends a file, the `cifs_setsize()` function fails to properly zero out the newly extended portion of the page cache.
This oversight can lead to stale data from the client's memory being written back to the server, potentially exposing sensitive information to the server. Red Hat severity: Moderate — CVSS 6.5 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N).
Weakness: CWE-201.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 38 minutes ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 38 minutes ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 38 minutes ago·verify at source
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