Bug 2466986 (CVE-2026-43079)

Summary:	CVE-2026-43079 kernel: perf/x86/intel/uncore: Skip discovery table for offline dies
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 `perf/x86/intel/uncore` component. This vulnerability occurs when Non-Uniform Memory Access (NUMA) is disabled and the system boots with fewer CPUs than available in a processor die. Under these conditions, the kernel continues to parse a discovery table for offline dies, leading to an array overflow. This issue may result in system instability or other undefined behavior.	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 10:01:55 UTC

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

perf/x86/intel/uncore: Skip discovery table for offline dies

This warning can be triggered if NUMA is disabled and the system
boots with fewer CPUs than the number of CPUs in die 0.

WARNING: CPU: 9 PID: 7257 at uncore.c:1157 uncore_pci_pmu_register+0x136/0x160 [intel_uncore]

Currently, the discovery table continues to be parsed even if all CPUs
in the associated die are offline.  This can lead to an array overflow
at "pmu->boxes[die] = box" in uncore_pci_pmu_register(), which may
trigger the warning above or cause other issues.

Comment 1 Alexander B 2026-05-06 15:08:39 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050613-CVE-2026-43079-d820@gregkh/T