Bug 2532144 (CVE-2026-89697)

Summary:	CVE-2026-89697 kernel: nfsd: add fh_want_write() for early-verified SETATTR in nfsd_proc_setattr()
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	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.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-11 20:55:08 UTC

In the Linux kernel, the following vulnerability has been resolved:

nfsd: add fh_want_write() for early-verified SETATTR in nfsd_proc_setattr()

The BOTH_TIME_SET branch calls fh_verify() early so setattr_prepare()
can inspect the dentry. This causes nfsd_setattr() to skip
fh_want_write(), so notify_change() runs without a mount write
reference.

Add the missing fh_want_write() call after the early fh_verify().