Bug 2507094 (CVE-2026-64473)

Summary:	CVE-2026-64473 kernel: vfio: Remove device debugfs before releasing devres
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	rhel-process-autobot, 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 VFIO (Virtual Function I/O) subsystem of the Linux kernel. During device unregistration, debugfs (a diagnostic filesystem) entries might remain visible with outdated or "stale" data after the associated resources have been released. This occurs because the debugfs entries are not removed before the device resources are deallocated. While primarily affecting diagnostic views, this could lead to an attacker observing incorrect system state.	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 2026-07-25 10:04:41 UTC

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

vfio: Remove device debugfs before releasing devres

VFIO device debugfs files created with debugfs_create_devm_seqfile()
store a devres allocated debugfs_devm_entry as inode private data.
vfio_unregister_group_dev() currently calls vfio_device_del() before
vfio_device_debugfs_exit(), but device_del() releases devres.  This can
leave debugfs entries visible with stale inode private data while
unregister waits for userspace references to drain.

Remove the per-device debugfs tree before vfio_device_del().  The debugfs
view is diagnostic only, so losing it at the start of unregister is
preferable to preserving entries whose backing storage may already have
been released.

Complete the teardown by clearing the per-device debugfs root after
removal.  This matches the global debugfs root cleanup and prevents
future users from mistaking a removed dentry for a live debugfs tree
during the remainder of unregister.

Comment 1 TEJ RATHI 2026-07-30 02:55:02 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072546-CVE-2026-64473-685a@gregkh/T