Bug 2467002 (CVE-2026-43117)

Summary:	CVE-2026-43117 kernel: Linux kernel: btrfs filesystem crash via incorrect superblock handling with overlayfs
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the btrfs filesystem component of the Linux kernel. When an overlay filesystem is used on top of btrfs, an incorrect superblock can be retrieved during the btrfs_sync_file() event. This misidentification can lead to a system crash, resulting in a Denial of Service (DoS).	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 2026-05-06 10:02:40 UTC

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

btrfs: tracepoints: get correct superblock from dentry in event btrfs_sync_file()

If overlay is used on top of btrfs, dentry->d_sb translates to overlay's
super block and fsid assignment will lead to a crash.

Use file_inode(file)->i_sb to always get btrfs_sb.

Comment 1 Alexander B 2026-05-06 14:22:04 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050627-CVE-2026-43117-8e20@gregkh/T