Bug 2559645 (CVE-2026-98937)

Summary:	CVE-2026-98937 kernel: kernel: information disclosure via unprivileged perf kernel callchain capture
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
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 Performance Events (perf) subsystem. The kernel failed to enforce proper privilege checks when capturing kernel callchains (call stack traces). A local unprivileged user could exploit this vulnerability to bypass profiling restrictions and collect kernel call stack data, leading to 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 2026-10-23 12:50:31 UTC

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

perf/core: Check kernel access when kernel callchains are requested

perf_event_open() currently gates perf_allow_kernel() only on
!attr.exclude_kernel.

However, users can still request kernel callchain collection with
attr.exclude_callchain_kernel == 0 even when attr.exclude_kernel == 1.
That still requires kernel profiling privilege, but the existing check
does not enforce it.

Update the permission check to call perf_allow_kernel() when either
kernel sampling is requested or kernel callchains are requested.

This keeps permission checks aligned with requested data and prevents
unprivileged use of kernel callchain capture.