Bug 2468232 (CVE-2026-43427)

Summary:	CVE-2026-43427 kernel: usb: class: cdc-wdm: fix reordering issue in read code path
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:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's USB CDC WDM driver. Due to compiler optimizations or CPU out-of-order execution, a memory reordering issue can occur during the read operation. This can lead to the driver accessing uninitialized memory, potentially resulting in information disclosure to a local attacker.	Story Points:	---
Clone Of:		Environment:
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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 2026-05-08 15:06:06 UTC

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

usb: class: cdc-wdm: fix reordering issue in read code path

Quoting the bug report:

Due to compiler optimization or CPU out-of-order execution, the
desc->length update can be reordered before the memmove. If this
happens, wdm_read() can see the new length and call copy_to_user() on
uninitialized memory. This also violates LKMM data race rules [1].

Fix it by using WRITE_ONCE and memory barriers.

Comment 1 Keith Grant 2026-05-08 23:25:30 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050849-CVE-2026-43427-12cc@gregkh/T