Bug 2492783 (CVE-2026-53167)

Summary:	CVE-2026-53167 kernel: fuse: limit FUSE_NOTIFY_RETRIEVE to uptodate folios
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 Linux kernel's FUSE (Filesystem in Userspace) component. The FUSE_NOTIFY_RETRIEVE operation did not properly restrict access to up-to-date folios, potentially allowing the exposure of uninitialized data from the page cache. This information disclosure vulnerability could allow an attacker to access sensitive information. This issue primarily affects systems where automatic zero-initialization of page allocations is not enabled.	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 2026-06-25 10:05:29 UTC

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

fuse: limit FUSE_NOTIFY_RETRIEVE to uptodate folios

FUSE_NOTIFY_RETRIEVE must be limited to uptodate folios; !uptodate folios
can contain uninitialized data.
Since FUSE_NOTIFY_RETRIEVE is intended to only return data that is already
in the page cache and not wait for data from the FUSE daemon, treat
!uptodate folios as if they weren't present.

This only has security impact on systems that don't enable automatic
zero-initialization of all page allocations via
CONFIG_INIT_ON_ALLOC_DEFAULT_ON or init_on_alloc=1.

Comment 1 TEJ RATHI 2026-06-26 08:15:17 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062551-CVE-2026-53167-e0b1@gregkh/T