Bug 2468231 (CVE-2026-43366)

Summary:	CVE-2026-43366 kernel: io_uring/kbuf: check if target buffer list is still legacy on recycle
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
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel. A vulnerability exists in the io_uring/kbuf component related to buffer recycling. There is a time gap where a buffer list, if empty, could be incorrectly upgraded to a ring-provided type. The legacy recycling mechanism fails to properly check the buffer list's existence and type, which could lead to system instability or unexpected behavior.	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 2026-05-08 15:06:02 UTC

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

io_uring/kbuf: check if target buffer list is still legacy on recycle

There's a gap between when the buffer was grabbed and when it
potentially gets recycled, where if the list is empty, someone could've
upgraded it to a ring provided type. This can happen if the request
is forced via io-wq. The legacy recycling is missing checking if the
buffer_list still exists, and if it's of the correct type. Add those
checks.

Comment 1 Keith Grant 2026-05-08 20:44:47 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050828-CVE-2026-43366-94ff@gregkh/T