Bug 2555060 (CVE-2026-98791)

Summary:	CVE-2026-98791 kernel: net/mlx5e: Fix AF_XDP TX timestamp teardown NULL dereference
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
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 Mellanox network driver (mlx5e). A local user can exploit this vulnerability to cause a denial of service (DoS) through a system crash. During the teardown of an AF_XDP (eXpress Data Path) transmit queue, outstanding descriptors requesting a transmit timestamp are completed without a completion queue entry, resulting in a NULL pointer dereference.	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 2026-10-18 15:52:11 UTC

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

net/mlx5e: Fix AF_XDP TX timestamp teardown NULL dereference

During XSK TX queue teardown, outstanding descriptors are completed
without a CQE. If one requested a TX timestamp, the completion path
passes that NULL CQE to mlx5e_xsk_fill_timestamp(), which dereferences
it.

Return zero when no CQE is available, indicating that teardown did not
produce a TX timestamp.

Comment 1 Mauro Matteo Cascella 2026-10-23 10:54:48 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98791.mbox