Bug 2562668 (CVE-2026-99177)

Summary:	CVE-2026-99177 kernel: kernel: Denial of Service via improper page dirtying locking in KVM SEV
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 KVM (Kernel-based Virtual Machine) subsystem. This vulnerability may lead to a Denial of Service (DoS) due to improper locking when marking guest memory pages as modified during AMD Secure Encrypted Virtualization (SEV) operations. A local user with permissions to manage virtual machines could trigger a race condition where memory mappings concurrently disappear, resulting in memory corruption and a system crash.	Story Points:	---
Clone Of:		Environment:
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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 2026-10-28 10:46:49 UTC

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

KVM: SEV: Fix page dirtying in sev_gmem_post_populate()

set_page_dirty() requires that the caller holds some kind of lock to
ensure that the page's mapping does not concurrently go away.
That is not the case for a random page we got from get_user_pages_fast(),
so use set_page_dirty_lock().

[sean: tag for stable]