Bug 2393733 (CVE-2025-39727)

Summary:	CVE-2025-39727 kernel: mm: swap: fix potential buffer overflow in setup_clusters()
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
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 (mm) swap component. A local attacker with low privileges could exploit a buffer overflow vulnerability in the `setup_clusters()` function. This issue arises from insufficient validation of page ranges, which could allow an attacker to write data beyond allocated memory boundaries. Successful exploitation could lead to a denial of service, information disclosure, or potentially privilege escalation.	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 2025-09-07 16:01:19 UTC

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

mm: swap: fix potential buffer overflow in setup_clusters()

In setup_swap_map(), we only ensure badpages are in range (0, last_page]. 
As maxpages might be < last_page, setup_clusters() will encounter a buffer
overflow when a badpage is >= maxpages.

Only call inc_cluster_info_page() for badpage which is < maxpages to fix
the issue.

Comment 1 Mauro Matteo Cascella 2025-09-09 08:03:18 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025090728-CVE-2025-39727-b07c@gregkh/

Comment 2 errata-xmlrpc 2025-10-27 18:31:39 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2025:19106 https://access.redhat.com/errata/RHSA-2025:19106

Comment 3 errata-xmlrpc 2025-11-12 12:22:11 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2025:21118 https://access.redhat.com/errata/RHSA-2025:21118