Bug 2536400 (CVE-2026-90228)

Summary:	CVE-2026-90228 kernel: nvmet: fix NULL pointer dereference in nvmet_execute_identify_ns_zns()
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 nvmet subsystem. A remote attacker can trigger a NULL pointer dereference by issuing a specific Identify command (CNS 05h, CSI 02h ZNS) targeting a file-backed namespace. This vulnerability occurs because the system attempts to access a block device that does not exist for file-backed namespaces. This can lead to a kernel panic, resulting in a Denial of Service (DoS).	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 17:43:58 UTC

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

nvmet: fix NULL pointer dereference in nvmet_execute_identify_ns_zns()

When a host issues an Identify command with CNS 05h (I/O Command Set
specific Identify Namespace) and CSI 02h (ZNS) targeting a file-backed
namespace, nvmet_execute_identify_ns_zns() calls bdev_is_zoned() on
req->ns->bdev. A file-backed namespace has no block device, so
req->ns->bdev is NULL and bdev_is_zoned() dereferences it, oopsing.

The I/O command set is selected by the host-supplied CSI field and the
command is routed here whenever CONFIG_BLK_DEV_ZONED is enabled,
independent of the namespace backing type, so any file-backed namespace
is exposed.

Reject the command with Invalid Field when the namespace is not backed
by a block device.

Comment 1 Mauro Matteo Cascella 2026-09-24 14:45:37 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90228.mbox