Bug 2554898 (CVE-2026-98451)

Summary:	CVE-2026-98451 kernel: smb: client: use finish_no_open() for non-regular inodes
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
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 SMB client. A local user can trigger this issue by opening an existing symbolic link or non-regular file on an SMB mount using file creation flags. Because the client improperly handles non-regular files during open operations, it fails to release directory entry references. This flaw leads to a resource leak, which can result in a denial of service (DoS) through resource exhaustion.	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 2026-10-18 15:26:32 UTC

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

smb: client: use finish_no_open() for non-regular inodes

An O_CREAT open can find an existing symlink or another non-regular
inode. cifs_atomic_open() calls finish_open() on it and attaches a
cifsFileInfo. Symlink inodes have no CIFS release operation, so the
dentry reference held by cifsFileInfo is leaked. FMODE_OPENED also
prevents the VFS from following the symlink.

Track whether cifs_do_create() returned an open server handle. For
non-regular inodes, close the handle if present, remove the pending
open, and call finish_no_open() so the VFS can continue the lookup.
Do not set FMODE_CREATED unless a regular file was opened. For
O_NOFOLLOW with __O_REGULAR, return -ELOOP before the VFS's
-EFTYPE check.

Defer closing a legacy POSIX handle on a non-regular inode until
after inode lookup. This avoids closing it again if lookup fails.

Comment 1 Mauro Matteo Cascella 2026-10-19 13:18:29 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98451.mbox