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CVE-2026-68390
Bluetooth: hci_sync: hold hdev->lock for hci_conn_params lookups
Published 2026-08-10 (2 months ago) by the Linux kernel CNA. Subsystem net/bluetooth. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-68390 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 | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | not affected | 6.12.113-1 | Nothing to do. trixie never shipped the vulnerable code. |
| Debian 14forky | fixed | 7.1.6-1 | Update the kernel and reboot. Fixed in 7.1.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.6-1 | Update the kernel and reboot. Fixed in 7.1.6-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
hci_conn_params_lookup requires hdev->lock be held, otherwise the list iteration or param access is not safe. Hold hdev->lock for params lookups in hci_sync.
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/hci_sync.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 -w CONFIG_BT /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
- M
- a module where it is built at all; some flavours do not build it
- Build switch
- CONFIG_BT
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
- 2026-08-10 (2 months 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
- 0.22%, higher than 11.5% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- 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 |
|---|---|---|
| 6.19 | 7.1.6 | 8d892bec1dd1 |
| 6.19 | 7.2 | c363202ec841 |
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 vulnerable hci_sync paths are Bluetooth LE host-stack code: hci_le_create_conn_sync is queued autonomously from check_pending_le_conn() on incoming LE advertising reports, and the racing hci_conn_params_del() side is driven by LE connection-complete/failure and disconnect events, so a device in radio range drives the bug over the air.
- AC:LAttack complexity, low
- The attacker controls both sides of the race — repeated LE connect/disconnect and PA-sync setup/teardown cycles queue the cmd_sync work while the event workqueue concurrently runs hci_conn_params_del()/hci_conn_del() under hdev->lock — and the sleeping hci_pause_advertising_sync() right before the unlocked lookup widens the window, so it can be retried until won.
- PR:NPrivileges required, none
- No credentials, pairing, or local account are needed: the host stack queues hci_le_create_conn_sync automatically in response to advertising reports from a device on the accept list, and the freeing side is triggered by connection-complete/failure events the peer controls.
- UI:NUser interaction, none
- Background LE scanning, auto-connect, accept-list programming, and connection-failure cleanup are performed autonomously by the kernel whenever connection state changes; no victim action such as pairing confirmation or opening a device is required.
- S:UScope, unchanged
- The corruption is confined to kernel heap objects owned by the Bluetooth subsystem within the same security authority; no hypervisor, IOMMU, or sandbox boundary is crossed.
- C:HConfidentiality impact, high
- hci_conn_params_lookup() iterates and dereferences a list entry that another CPU may have list_del()'d and kfree()'d, and hci_le_pa_create_sync() reads le->dst/le->handle from a possibly freed hci_conn; a groomed slab yields an arbitrary read primitive, and the stale values are copied into the outgoing HCI command, leaking kernel heap contents over the air.
- I:HIntegrity impact, high
- This is a classic slab use-after-free on hci_conn_params/hci_conn: reclaiming the freed object with attacker-controlled data gives write and control-flow primitives, and the corrupted values are written into conn->le_conn_* fields and the HCI command payload, so kernel memory corruption and privilege escalation are leverageable.
- A:HAvailability impact, high
- Walking le_conn_params without hdev->lock while an entry is removed dereferences LIST_POISON1 or freed memory, producing slab-use-after-free KASAN splats, oopses, or a kernel panic in the Bluetooth workqueues.