Bug 2554915 (CVE-2026-98634)

Summary:	CVE-2026-98634 kernel: scsi: sd_zbc: Reject disks with too many zones
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 SCSI ZBC (Zoned Block Commands) driver. This vulnerability can lead to a denial of service (DoS) when the system attempts to scan a storage device that reports an excessively large number of zones. Due to integer truncation and overflow during zone calculations, the kernel allocates insufficient resources and fails to manage zone state properly. An attacker capable of connecting a specially crafted storage device could exploit this issue to trigger inconsistent internal bookkeeping and crash the system.	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 2026-10-18 15:32:09 UTC

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

scsi: sd_zbc: Reject disks with too many zones

sd_zbc_read_zones() computes the number of zones with 64-bit arithmetic and
stores the result in the unsigned int nr_zones field of struct
zoned_disk_info, silently truncating counts that exceed 32 bits. The
truncated count is later used to size per-zone resources, while the device
may still report more zones than fit.

Moreover, sd_zbc_report_zones() counts the reported zones with a signed int
zone_idx, which overflows past INT_MAX. Reject devices reporting more than
INT_MAX zones at scan time; such a device is not realistic for any medium
that exists today, and accepting it produces inconsistent zone bookkeeping.