Bug 2562758 (CVE-2026-99160)

Summary:	CVE-2026-99160 kernel: kernel: Denial of Service via null pointer dereference in ring buffer metadata
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 local user can exploit this vulnerability to cause a Denial of Service (DoS) by crashing the kernel. The issue occurs when reading ring buffer metadata files for a central processing unit (CPU) that has never come online, resulting in a null pointer dereference.	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 2026-10-28 11:04:50 UTC

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

ring-buffer: Do not show buffer_meta for CPUs without a buffer

The per_cpu/cpuN/buffer_meta files are created for every possible CPU,
but buffer->buffers[cpu] is only allocated once that CPU comes online.
Reading the file of a CPU that never came online dereferences a NULL
cpu_buffer in rbm_start().

Fail the open with -ENODEV when the CPU has no buffer, as the other
per CPU ring buffer interfaces do.