Bug 2566140 (CVE-2026-99245)

Summary:	CVE-2026-99245 kernel: kernel: Keyring restriction bypass via race condition in key_reject_and_link()
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
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. A local user could bypass keyring link restrictions due to a race condition in the kernel's key management subsystem. This issue occurs when the kernel checks link restrictions before acquiring the necessary lock during key linking operations, racing against concurrent restriction updates. An attacker can exploit this timing window to insert unauthorized keys into a restricted keyring, bypassing intended kernel security controls.	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 2026-11-03 19:33:47 UTC

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

KEYS: Fix key_reject_and_link() race with keyring restriction

The restrict_link check in key_reject_and_link() is done before taking
the keyring semaphore, racing with a concurrent keyring_restrict()
that installs the restriction while holding the semaphore in write
mode.

Move the check to after __key_link_lock(), so it is done under the
semaphore, matching the pattern used in __key_create_or_update().