Bug 2559812 (CVE-2026-99013)

Summary:	CVE-2026-99013 kernel: Bluetooth: ISO: Reject concurrent BIS listener 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 local user could cause a Denial of Service (DoS) due to a race condition during concurrent setup of Broadcast Isochronous Stream (BIS) socket listeners. By issuing simultaneous listen calls on the same broadcast socket, an attacker can trigger a use-after-free memory error, leading to a system crash.	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 13:45:08 UTC

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

Bluetooth: ISO: Reject concurrent BIS listener setup

iso_sock_listen() drops the socket lock before calling iso_listen_bis()
to preserve the hdev->lock ordering. Two concurrent listen() calls on
the same broadcast socket can therefore both observe BT_BOUND. Caller
A can attach connA and release the locks, then caller B can acquire
them and attach connB before A publishes BT_LISTEN.

__iso_chan_add() checks whether connB already has a socket, but not
whether the socket already has a connection. The second attachment
overwrites iso_pi(sk)->conn, leaking the connA reference and leaving
connA->sk intact. Socket teardown follows connB, so later events on
connA can cause a stale socket access.

Recheck BT_BOUND and require iso_pi(sk)->conn to be NULL after taking
both the HCI device and socket locks in iso_listen_bis(). The connection
check also covers the interval between attachment and publication of
BT_LISTEN. Reject a competing setup with -EBADFD through the existing
unlock path before allocating another connection.

A recorded KASAN report from an instrumented kernel shows:

  BUG: KASAN: slab-use-after-free in iso_sock_hold+0x119/0x1f0
  Call Trace:
   iso_sock_hold+0x119/0x1f0
   iso_conn_del+0xe4/0x270
   hci_disconn_complete_evt+0x351/0x8c0
   hci_event_packet+0x71b/0xb20
   hci_rx_work+0x293/0x730

  Allocated by task 93:
   sk_prot_alloc+0x113/0x220
   sk_alloc+0x2b/0x6d0
   bt_sock_alloc+0x29/0x370
   iso_sock_alloc.constprop.0+0x19/0x300
   iso_sock_create+0x94/0x100

  Freed by task 93:
   kfree+0x121/0x3c0
   __sk_destruct+0x42b/0x540
   iso_sock_release+0x29d/0x340
   __sock_release+0xa1/0x260
   sock_close+0x10/0x20