Bug 2546490 (CVE-2026-98281)

Summary:	CVE-2026-98281 kernel: futex: Also allocate private hash on vfork()
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 Fast Userspace Mutex (futex) subsystem. A local user could trigger this flaw by creating a process using the vfork system call, which shares virtual memory with the parent process without properly initializing a private futex hash table. This issue can cause inconsistent state in futex wait queues, potentially leading to a Denial of Service (DoS) or kernel memory corruption.	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 2026-10-06 09:31:09 UTC

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

futex: Also allocate private hash on vfork()

As Jann demonstrated, it is entirely feasible to access the mm through vfork().
Therefore we need to allocate a private hash on vfork() as well as any other
CLONE_VM user.

Specifically, it must be avoided to have (private) futex waiters before
allocating the private hash.

Comment 1 gkamathe 2026-10-10 21:51:00 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98281.mbox