Bug 2541052 (CVE-2026-98019)

Summary:	CVE-2026-98019 kernel: bpf: mark a NULL call argument precise
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 Berkeley Packet Filter (BPF) verifier. The verifier failed to mark scalar registers as precise when checking null function arguments and specific helper call parameters, causing its state-tracking logic to improperly prune verification paths. A local attacker with permission to load BPF programs could exploit this flaw using a specially crafted program to bypass safety checks, potentially leading to privilege escalation or a denial of service.	Story Points:	---
Clone Of:		Environment:
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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 10:44:59 UTC

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

bpf: mark a NULL call argument precise

check_func_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

check_helper_call() enforces second parameter of the
bpf_get_local_storage() to be zero, w/o marking the underlying scalar
register precise. Hence a checkpoint created on such a path would
prune against arbitrary scalar value.

Grouping these two into one patch, as they share the same fixes tag.

Comment 1 Keith Grant 2026-09-28 20:40:26 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98019.mbox