Bug 2350584 (CVE-2025-21836)

Summary:	CVE-2025-21836 kernel: io_uring/kbuf: re-using old struct io_buffer_list may lead to a use-after-free situation
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:	dfreiber, drow, jburrell, vkumar
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
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Description OSIDB Bzimport 2025-03-07 10:01:06 UTC

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

io_uring/kbuf: reallocate buf lists on upgrade

IORING_REGISTER_PBUF_RING can reuse an old struct io_buffer_list if it
was created for legacy selected buffer and has been emptied. It violates
the requirement that most of the field should stay stable after publish.
Always reallocate it instead.

Comment 1 Michal Findra 2025-03-07 15:34:59 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025030706-CVE-2025-21836-b358@gregkh/T