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CVE-2026-80914
Bluetooth: ISO: fix use-after-free of listener socket in iso_conn_ready
Published 2026-09-09 (39 days ago) by the Linux kernel CNA. Subsystem net/bluetooth. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-80914 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixedDLA-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
iso_conn_ready() looks up the BIS listener socket with iso_get_sock(), which takes a reference, and then, without re-checking its state, creates a child socket from it: parent = iso_get_sock(hdev, ...); if (!parent) return; lock_sock(parent); sk = iso_sock_alloc(sock_net(parent), NULL, BTPROTO_ISO, ...); ... iso_chan_add(conn, sk, parent); ... release_sock(parent); sock_put(parent); If the listener socket is closed concurrently, between iso_get_sock() and lock_sock(), the reference taken by iso_get_sock() may be the last one: the close path drops the link-list reference, and once iso_conn_ready() drops its own reference at the end of the function the socket is freed. The child socket, however, is already linked to the freed parent, and a later disconnect of the child runs iso_chan_del() -> bt_accept_unlink(), which dereferences the dangling parent pointer into the freed accept queue (a use-after-free). The same dangling pointer is also dereferenced through parent->***() in iso_chan_del(). Fix it the same way the connected (non-BIS) path was fixed in commit 0d255e63fcf3 ("Bluetooth: ISO: hold sk properly in iso_conn_ready"): after taking the socket lock, re-check that the parent is still a listening, alive socket, and bail out otherwise.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
net/bluetooth/iso.c
- What this is
- BLUETOOTH SUBSYSTEMMAINTAINERS section matched on net/bluetooth/ · linux-bluetooth@vger.kernel.org · Supported
- Kernel module
- bluetooth
Check it on the machine
grep -wE 'CONFIG_BT|CONFIG_BT_LE' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w bluetoothPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookwormMnot built on amd64/cloud-amd64, arm64/cloud-arm64
- trixie, forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, s390x/s390x
- bookworm · linux-6.12Mnot built on amd64/cloud-amd64, arm64/cloud-arm64
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_BT, CONFIG_BT_LE
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-09-09 (39 days ago)source
- CVSS
- 8.8 high
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- adjacent network (AV:A)source
- EPSS
- 0.23%, higher than 13.1% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/bluetooth
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.0 | 6.1.188 | 1702f12cf59a |
| 6.0 | 6.6.157 | d47b8f8c02a3 |
| 6.0 | 6.12.109 | 2387cd06a2c0 |
| 6.0 | 6.18.50 | 49fd7116f76b |
| 6.0 | 7.2.4 | 03288b7447c9 |
| 6.0 | 7.3 | 560bef609fa5 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | tracker |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:AAttack vector, adjacent network
- The UAF is in Bluetooth ISO iso_conn_ready() parent-lookup for incoming CIS/BIS/PA; that path runs from HCI connect_cfm events (hci_le_cis_req_evt, BIG/PA sync) driven by LE isochronous traffic from peers in radio range, which is an adjacent attack surface.
- AC:LAttack complexity, low
- This is a use-after-free race between iso_get_sock() and listener close (iso_sock_release/iso_sock_kill) before lock_sock(); an attacker who opens/closes an ISO listen socket while concurrent HCI CIS/BIS/PA completion runs controls both sides and can trigger it without uncontrollable conditions.
- PR:NPrivileges required, none
- iso_sock_create has no capability check, and the vulnerable path is reached from unauthenticated HCI CIS/BIG/PA events processed for any Bluetooth-enabled device in range; listener close can occur from automatic LE Audio/bluetoothd teardown without privileged local credentials.
- UI:NUser interaction, none
- No victim action is required: iso_connect_ind returns HCI_LM_ACCEPT so incoming CIS/BIS/PA sync is auto-accepted when an ISO listener exists, and OS LE Audio stacks keep such listeners during normal broadcast/unicast operation.
- S:UScope, unchanged
- The UAF corrupts kernel socket/accept-queue memory and can enable privilege escalation within the host kernel; it does not cross a VM, container, or IOMMU security boundary, so scope remains unchanged.
- C:HConfidentiality impact, high
- Use-after-free of the listener struct sock (and later bt_accept_unlink of the dangling parent) lets an attacker reuse the freed sock/accept-queue object, enabling arbitrary kernel memory disclosure via heap grooming per UAF guidance.
- I:HIntegrity impact, high
- The child is linked to the freed parent via iso_chan_add/bt_accept_enqueue; later iso_chan_del -> bt_accept_unlink writes the freed parent's accept queue (list_del, sk_acceptq_removed), a kernel heap write primitive usable for control-flow hijack.
- A:HAvailability impact, high
- Dereferencing the freed listener in iso_chan_del/bt_accept_unlink (accept_q_lock, list, parent->sk_data_ready) causes kernel oops/panic; UAFs in this ISO path are a high availability impact even before full exploitation.