Bug 2532480 (CVE-2026-89728)

Summary:	CVE-2026-89728 kernel: i3c: renesas: Fix out-of-bounds access for newdevs mask
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 I3C Renesas driver. When the I3C bus is empty and software initiates Dynamic Address Assignment (DAA), an out-of-bounds access can occur. This is due to an incorrect calculation of the newly discovered devices bitmask, which can lead to system instability or other undefined behavior.	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 2026-09-11 23:24:10 UTC

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

i3c: renesas: Fix out-of-bounds access for newdevs mask

When software initiates DAA (Dynamic Address Assignment), the controller
reports the result via the NRSPQP (Normal Response Queue Port Register).
The data length field of the response descriptor, which is accessible
through the NRSPQP register, indicates the number of devices remaining
after DAA. Consequently, when the bus is empty, this field contains the
maximum number of devices supported by the controller (8 for the Renesas
I3C controller).

Adjust the condition that computes the newly discovered devices bitmask
to prevent an out-of-bounds when the I3C bus is empty.

Comment 1 Mauro Matteo Cascella 2026-09-15 13:39:45 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89728.mbox