Bug 2536482 (CVE-2026-92509)

Summary:	CVE-2026-92509 kernel: RDMA/core: Fix potential use after free in counter_release()
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 RDMA (Remote Direct Memory Access) core component. When a counter is accessed via the netlink path, the `rdma_restrack_del()` function is invoked too late during the `counter_release()` process. This timing issue can lead to a use-after-free vulnerability, where vendor-specific resources associated with the counter might be freed while the counter remains accessible, potentially allowing an attacker to exploit the freed memory.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
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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 2026-09-17 18:10:17 UTC

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

RDMA/core: Fix potential use after free in counter_release()

When accessing a counter via the netlink path the only synchronization
mechanism for the said counter is rdma_restrack_get().
Currently, rdma_restrack_del() is invoked at the end of
counter_release(), which is too late, since by that point
vendor-specific resources associated with the counter might already be
freed. This can leave a short window where the counter remains
accessible through restrack, leading to a potential use-after-free.

Fix this by moving the rdma_restrack_del() call to be before the
freeing of the vendor-specific resources, ensuring that the counter is
removed from restrack before its internal resources are released.
This guarantees that no new users hold references to a counter that is
in the process of destruction.

Comment 1 gkamathe 2026-09-21 01:03:19 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-92509.mbox