Bug 2492788 (CVE-2026-53189)

Summary:	CVE-2026-53189 kernel: mm/huge_memory: update file PMD counter before folio_put()
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 memory management, specifically within the huge page mechanism. When a huge page is split, the system updates a counter after releasing a reference to the memory. This timing issue can lead to the system attempting to read from memory that has already been freed, potentially resulting in memory corruption or information disclosure.	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 10:05:46 UTC

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

mm/huge_memory: update file PMD counter before folio_put()

__split_huge_pmd_locked() updates the file/shmem RSS counter after
dropping the PMD mapping's folio reference.  If folio_put() drops the last
reference, mm_counter_file() can later read freed folio state via
folio_test_swapbacked().

Move the counter update before folio_put().

Comment 1 TEJ RATHI 2026-06-26 07:57:29 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062557-CVE-2026-53189-1b4a@gregkh/T