Bug 2541278 (CVE-2026-97617)

Summary:	CVE-2026-97617 kernel: ring-buffer: Check resize_disabled before publishing the new subbuf order
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:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, 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 ring buffer subsystem. A race condition occurs when updating the buffer configuration concurrently with memory mapping operations. Because the kernel applies the new buffer order before verifying that resizing is permitted across all processors, the system can map out-of-bounds memory pages. A local user could exploit this vulnerability to cause memory corruption or a denial of service (DoS) through a system crash.	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 2026-09-25 11:14:21 UTC

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

ring-buffer: Check resize_disabled before publishing the new subbuf order

ring_buffer_subbuf_order_set() stores the new order and only then walks
the CPUs, returning -EBUSY if any of them has resizing disabled. A user
mapped buffer has resizing disabled, and __rb_map_vma() reads
buffer->subbuf_order without buffer->mutex, so an mmap of an already
mapped CPU racing the failing order change sizes the mapping with the
new order and inserts pages past the sub-buffer into the VMA.

Check the CPUs before storing the new order.

Comment 1 Keith Grant 2026-09-29 15:30:37 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97617.mbox