Bug 2532181 (CVE-2026-89447)

Summary:	CVE-2026-89447 kernel: iommufd: Avoid locking internal accesses during unmap
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
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 iommufd subsystem. A local attacker could exploit a vulnerability where an object reference is leaked during the unmapping of internal accesses. This occurs because the `iommufd_access_notify_unmap()` function incorrectly locks an object before checking if the access is internal, leading to the object reference not being released. This resource leak could potentially lead to a denial of service.	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 21:09:52 UTC

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

iommufd: Avoid locking internal accesses during unmap

iommufd_access_notify_unmap() skips internal accesses because they do
not have an external unmap callback to invoke.

However, the current test calls iommufd_lock_obj() before checking
whether the access is internal. If iommufd_lock_obj() succeeds, the loop
then sees the internal access and continues, bypassing the matching
iommufd_put_object() used by the normal unmap path. This leaks the
object reference taken by iommufd_lock_obj().

Check for internal accesses first so skipped entries are never locked.

Comment 1 Mauro Matteo Cascella 2026-09-17 18:16:56 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89447.mbox