Bug 2536422 (CVE-2026-92520)

Summary:	CVE-2026-92520 kernel: bpf: Zero queue and stack outputs on lock failure
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) component. When BPF queue and stack pop/peek helpers fail to acquire a lock, they can return without properly initializing the output buffer. This allows a local attacker, by running a specially crafted BPF program, to observe uninitialized stack contents, potentially 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 2026-09-17 17:46:30 UTC

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

bpf: Zero queue and stack outputs on lock failure

Queue and stack pop/peek helpers accept an uninitialized output buffer
because the verifier expects the helper to initialize it. The empty-map
error path clears the buffer, but a failed lock acquisition returns
-EBUSY without writing it.

Clear the output before returning -EBUSY so BPF programs cannot observe
uninitialized stack contents after a failed helper call.

Comment 1 gkamathe 2026-09-21 05:40:19 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-92520.mbox