Bug 2541123 (CVE-2026-97977)

Summary:	CVE-2026-97977 kernel: Bluetooth: btusb: Fix UAF of btusb_data by rx_work
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 Bluetooth USB driver. A race condition during device closure or disconnection allows background receive tasks to continue running after the associated device data has been released, leading to a use-after-free (UAF) condition. A local attacker could exploit this flaw to cause a Denial of Service (DoS) by crashing the system or potentially achieve arbitrary code execution.	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 2026-09-25 10:50:19 UTC

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

Bluetooth: btusb: Fix UAF of btusb_data by rx_work

btusb_close() and btusb_flush() cancel data->rx_work with the
asynchronous cancel_delayed_work(), so if btusb_rx_work() is already
running on another CPU it keeps running after the cancel returns.

btusb_disconnect() calls hci_unregister_dev(), which invokes
btusb_close(), and then frees the btusb_data. A still running
btusb_rx_work() then dereferences the freed data:

	while ((skb = skb_dequeue(&data->acl_q)))
		data->recv_acl(data->hdev, skb);

Use cancel_delayed_work_sync() instead. In btusb_close() the cancel also
has to happen after btusb_stop_traffic(), otherwise an URB completion
racing with the cancel can requeue the work right after it has been
waited for.

Comment 1 gkamathe 2026-09-30 06:02:48 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97977.mbox