Medium [CVE-2026-89697] Linux kernel: NFS daemon bypasses write verification during attribute setting
This medium-severity Red Hat Linux advisory covers CVE-2026-89697.
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Summary
A flaw was found in the Linux kernel's Network File System Daemon (nfsd). When setting file attributes using `nfsd_proc_setattr()`, a specific code path (`BOTH_TIME_SET` branch) prematurely verifies file handles.
This bypasses a critical write verification step (`fh_want_write()`), allowing file attribute changes to proceed without a proper mount write reference. This could lead to unauthorized modification of file metadata or content, potentially impacting data integrity.
Red Hat severity: Important — CVSS 6.8 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H). Weakness: CWE-911.
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 2 hours 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 2 hours 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 2 hours ago·verify at source
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