Bug 2541039 (CVE-2026-98018)

Summary:	CVE-2026-98018 kernel: net: mctp: i3c: serialize probe with bus removal
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
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. A race condition in the Management Component Transport Protocol (MCTP) I3C driver occurs when device discovery releases a lock prematurely while a bus is simultaneously removed. A local user could exploit this synchronization flaw to access freed memory, resulting in a system crash and Denial of Service (DoS) or potential privilege escalation.	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 2026-09-25 10:44:49 UTC

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

net: mctp: i3c: serialize probe with bus removal

mctp_i3c_probe() drops busdevs_lock after finding the matching bus. A
concurrent I3C_NOTIFY_BUS_REMOVE can then unregister and free the bus
netdev before probe passes its private data to mctp_i3c_add_device().
The latter consequently adds a list node through a freed mbus pointer.

Keep busdevs_lock held until the device has been added. This also
satisfies the __must_hold annotation on mctp_i3c_add_device().

Comment 1 Keith Grant 2026-09-28 20:33:55 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98018.mbox