Bug 2554890 (CVE-2026-98492)

Summary:	CVE-2026-98492 kernel: net: macb: fix dma_alloc_coherent() leak on macb_alloc() error paths
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 Cadence MACB network driver. During network buffer allocation, the driver's error-handling routines fail to properly release allocated Direct Memory Access (DMA) memory buffers when a failure occurs. A local user could trigger these error conditions during device initialization or interface setup, causing kernel memory to leak. Over time, this unreleased memory can result in system resource exhaustion and a Denial of Service (DoS).	Story Points:	---
Clone Of:		Environment:
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Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-10-18 15:25:48 UTC

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

net: macb: fix dma_alloc_coherent() leak on macb_alloc() error paths

Fix 3 leaks in macb_alloc() error paths:
- Tx buffer allocated but crossing a 4G boundary: Tx leaked.
- Rx buffer allocation fails: Tx leaked.
- Rx buffer allocated but crossing a 4G boundary: Tx & Rx leaked.

This is because our error handling calls macb_free(bp) which in turn
frees the buffers stored in bp->queues[0], but nothing has been stored
in there. Fix by storing allocated buffers into bp->queues[0] ASAP.

Comment 1 Mauro Matteo Cascella 2026-10-20 12:59:29 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98492.mbox