Bug 2559733 (CVE-2026-99014)

Summary:	CVE-2026-99014 kernel: Bluetooth: hci_sync: Fix command skb lifetime during scan setup
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 subsystem. A race condition between concurrent worker threads during Periodic Advertising (PA) sync scan setup can cause a command buffer to be freed while still in use. A local attacker could exploit this use-after-free flaw to cause a Denial of Service (DoS) by crashing the system or potentially escalate privileges.	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 2026-10-23 13:25:32 UTC

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

Bluetooth: hci_sync: Fix command skb lifetime during scan setup

During PA sync scan setup, hci_le_set_ext_scan_param_sync() gets the
address used for the PA_LINK lookup from hci_sent_cmd_data(). The
returned pointer borrows storage from sent_cmd or req_skb, without
holding a reference to either skb.

The scan worker runs on req_workqueue while hci_cmd_work() runs on the
separate device workqueue. After the scan worker loads sent_cmd, the
command worker can free and replace it before hci_sent_cmd_data()
dereferences the skb. The command payload can also be freed between
returning from the helper and comparing the address. The connection
lookup's RCU critical section does not protect the command skb.

KASAN reported:

  BUG: KASAN: slab-use-after-free in hci_sent_cmd_data+0x27c/0x2f0
  Workqueue: hci0 hci_cmd_sync_work
  Call Trace:
   hci_sent_cmd_data+0x27c/0x2f0
   hci_le_set_scan_param_sync+0x43a/0x850
   hci_passive_scan_sync+0xb09/0x1460
   hci_update_passive_scan_sync+0x47c/0x6e0
   hci_le_pa_create_sync+0x200/0xa70
   hci_cmd_sync_work+0x13c/0x290

  Allocated by task 95:
   skb_clone+0x13f/0x340
   hci_cmd_work+0x2a9/0x7e0

  Freed by task 95:
   kmem_cache_free+0xba/0x3a0
   hci_cmd_work+0x29c/0x7e0

Use hdev->lock to serialize the address snapshot with sent_cmd
replacement. Protect req_skb replacement and completion cleanup with
the same lock because the helper falls back to that skb. Copy the
address before releasing the lock and use the copy for the existing
RCU-protected connection lookup. Release the mutex before sending or
waiting for commands, preserving the lookup and completion ordering.