Bug 2554868 (CVE-2026-98458)

Summary:	CVE-2026-98458 kernel: Bluetooth: ISO: release unused CIS holds after channel attach
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's Bluetooth subsystem. A local attacker can cause a Denial of Service (DoS) through a reference count leak during Bluetooth Isochronous (ISO) channel attachment. When a socket attempts to attach to a channel that is already connected or in use by another socket, the kernel fails to release acquired connection holds. Repeated connection attempts under these conditions can prevent connection resources from being freed, resulting in system resource exhaustion.	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 2026-10-18 15:24:14 UTC

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

Bluetooth: ISO: release unused CIS holds after channel attach

hci_bind_cis() and hci_connect_cis() return one hci_conn hold for the
ISO layer.  A new channel association consumes that hold, which is
eventually released by iso_conn_free().

There are two cases where iso_chan_add() does not create an association:
it returns success when the socket is already attached to the same
iso_conn, and it returns -EBUSY when another socket is attached.  The
hold returned for the current call is unused in both cases.  This occurs
when deferred setup calls iso_connect_cis() again for its existing
socket, or when another socket attempts to reuse the CIS.

Detect the idempotent case while the connection is locked and release
the unused hold after iso_chan_add().  Also release it on -EBUSY.  Do not
drop it for other errors: a newly allocated iso_conn releases the
transferred hold when its last temporary reference is put.

Comment 1 Mauro Matteo Cascella 2026-10-19 14:59:09 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98458.mbox