Bug 2467059 (CVE-2026-43163)

Summary:	CVE-2026-43163 kernel: md/bitmap: fix GPF in write_page caused by resize race
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 Linux kernel's md/bitmap component. This vulnerability involves a use-after-free race condition that occurs during array resize operations. When the `bitmap_daemon_work()` and `__bitmap_resize()` functions execute concurrently, they can access memory pages that have already been freed. This can lead to a General Protection Fault (GPF), which causes the system to crash, resulting in a denial of service.	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 13:02:06 UTC

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

md/bitmap: fix GPF in write_page caused by resize race

A General Protection Fault occurs in write_page() during array resize:
RIP: 0010:write_page+0x22b/0x3c0 [md_mod]

This is a use-after-free race between bitmap_daemon_work() and
__bitmap_resize(). The daemon iterates over `bitmap->storage.filemap`
without locking, while the resize path frees that storage via
md_bitmap_file_unmap(). `quiesce()` does not stop the md thread,
allowing concurrent access to freed pages.

Fix by holding `mddev->bitmap_info.mutex` during the bitmap update.

Comment 1 Keith Grant 2026-05-06 19:27:36 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050632-CVE-2026-43163-86e1@gregkh/T