Bug 2528746 (CVE-2026-80880)

Summary:	CVE-2026-80880 kernel: IB/mlx5: Properly support implicit ODP rereg_mr
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's `IB/mlx5` component. Improper handling of implicit On-Demand Paging (ODP) memory registration (`rereg_mr`) and interactions with child memory keys can lead to a race condition. This occurs because changes to a parent memory key necessitate a complete rebuild, and implicit child keys can concurrently access the memory protection domain (`mr->pd`). This race condition could result in unpredictable system behavior or potential memory corruption.	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 2026-09-04 17:18:06 UTC

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

IB/mlx5: Properly support implicit ODP rereg_mr

Due to all the child mkeys in the implicit ODP configuration we cannot
change anything in place for the parent mkey. Instead the whole thing
needs to be rebuilt if any change is requested. If the user does not
specify a translation then force the implicit values which will then fall
through the logic into mlx5_ib_reg_user_mr() to allocate a completely new
MR.

Since implicit children were also touching the mr->pd, this removes
another case where the access was racy.

Comment 1 Mauro Matteo Cascella 2026-09-08 10:09:49 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80880.mbox