Bug 2516265 (CVE-2026-72032)

Summary:	CVE-2026-72032 kernel: net/mlx5: HWS, fix matcher leak on resize target setup failure
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:	rhel-process-autobot, 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 net/mlx5 HWS (Hardware Steering) component. This vulnerability occurs when the hws_bwc_matcher_move() function attempts to resize a matcher, and the mlx5hws_matcher_resize_set_target() operation fails. In such a scenario, a replacement matcher is allocated but not properly deallocated, leading to a memory leak. Over time, repeated occurrences of this flaw could potentially lead to a Denial of Service (DoS) due to resource exhaustion.	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 2026-08-15 06:03:24 UTC

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

net/mlx5: HWS, fix matcher leak on resize target setup failure

hws_bwc_matcher_move() allocates a replacement matcher before setting it
as the resize target. If mlx5hws_matcher_resize_set_target() fails, the
replacement matcher is not attached anywhere and is leaked.

Fix the leak by destroying the replacement matcher before returning from
the resize-target failure path.

The bug was first flagged by an experimental analysis tool we are
developing for kernel memory-management bugs while analyzing
v6.13-rc1. The tool is still under development and is not yet publicly
available. Manual inspection confirms that the bug is still
present in v7.1.1.

An x86_64 allyesconfig build showed no new warnings. As we do not have a
mlx5 HWS-capable device to test with, no runtime testing was able to be
performed.

Comment 1 Keith Grant 2026-08-17 16:54:15 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081512-CVE-2026-72032-bc57@gregkh/T