Bug 2535376 (CVE-2026-89854)

Summary:	CVE-2026-89854 kernel: scsi: qla2xxx: Fix cs84xx use-after-free on host teardown
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 kernel's qla2xxx SCSI driver. A use-after-free vulnerability exists due to a race condition during host teardown. When a host is being removed, the cs84xx object can be freed before its corresponding sysfs attribute is removed. A local attacker, by concurrently reading this attribute, can trigger a dereference of the freed memory, leading to system instability or 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 2026-09-16 12:24:41 UTC

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

scsi: qla2xxx: Fix cs84xx use-after-free on host teardown

qla84xx_put_chip() drops the last reference to ha->cs84xx and frees it via
__qla84xx_chip_release() without clearing ha->cs84xx. During teardown it ran
before scsi_remove_host(), which is what removes the 84xx_fw_version host
sysfs attribute. A concurrent read of that attribute in the window between
the two calls executes qla24xx_84xx_fw_version_show(), which dereferences
the freed ha->cs84xx, resulting in a use-after-free.

Move qla84xx_put_chip() to after scsi_remove_host() in both
qla2x00_remove_one() and qla2x00_disable_board_on_pci_error(). Once
scsi_remove_host() returns, the sysfs attribute is gone and kernfs has
drained any in-flight show(), so no reader can touch cs84xx; the put still
runs before the host and ha are freed.

Comment 1 Keith Grant 2026-09-23 11:45:18 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89854.mbox