Bug 2467008 (CVE-2026-43092)

Summary:	CVE-2026-43092 kernel: xsk: validate MTU against usable frame size on bind
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
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 AF_XDP (eXpress Data Path) subsystem. The AF_XDP bind operation fails to validate the Maximum Transmission Unit (MTU) against the usable frame space provided by the UMEM (User Memory) chunk. This can lead to situations where the configured MTU does not fit, potentially causing network communication failures or system instability. A local attacker could potentially leverage this vulnerability to disrupt network services, resulting in a denial of service.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
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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 2026-05-06 10:02:57 UTC

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

xsk: validate MTU against usable frame size on bind

AF_XDP bind currently accepts zero-copy pool configurations without
verifying that the device MTU fits into the usable frame space provided
by the UMEM chunk.

This becomes a problem since we started to respect tailroom which is
subtracted from chunk_size (among with headroom). 2k chunk size might
not provide enough space for standard 1500 MTU, so let us catch such
settings at bind time. Furthermore, validate whether underlying HW will
be able to satisfy configured MTU wrt XSK's frame size multiplied by
supported Rx buffer chain length (that is exposed via
net_device::xdp_zc_max_segs).

Comment 1 Alexander B 2026-05-06 14:11:52 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050618-CVE-2026-43092-883d@gregkh/T