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CVE-2026-68392
Bluetooth: mgmt: fix locking in unpair_device/disconnect_sync
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-2026-68392 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 | fixed | 6.12.101-1 | Update the kernel and reboot. Fixed in 6.12.101-1. A running kernel keeps the old code until the machine restarts. |
| 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. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4745-1 · 2026-08-18 · text | 6.12.101-1~deb12u1 | Update the kernel and reboot. DLA-4745-1 shipped the fix on 2026-08-18, in 6.12.101-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Dereferencing RCU-protected pointers outside critical sections is invalid and may lead to UAF. Take hdev->lock for hci_conn lookup and hci_abort_conn(). Don't use RCU to ensure the conn is fully initialized at this point.
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/mgmt.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
- 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 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
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.3% 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 |
|---|---|---|
| 6.1.184 | 6.1.184 | 74f3e6e21ebc |
| 6.6.51 | 6.6.148 | 8bc83f9ef678 |
| 6.11 | 6.12.101 | 579faba5ede6 |
| 6.11 | 6.18.42 | ca58ad287bfc |
| 6.11 | 7.1.6 | b11511006f9e |
| 6.11 | 7.2 | 16cd66443957 |
| 6.10.10 | 0 | 0 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4745-1 | 2026-08-18 | bookworm 6.12.101-1~deb12u1 | 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:LAttack vector, local
- The vulnerable path is entered by a local process sending MGMT_OP_DISCONNECT/MGMT_OP_UNPAIR_DEVICE on an AF_BLUETOOTH/BTPROTO_HCI socket bound to HCI_CHANNEL_CONTROL, and the freeing side is drivable locally via /dev/vhci events or ioctl(HCIDEVDOWN)/hci_conn_hash_flush; no over-the-air access is required.
- AC:LAttack complexity, low
- The attacker controls both sides of the race — repeatedly queuing the mgmt command while tearing the connection down (vhci-injected disconnect-complete, HCIDEVDOWN, or connection timeout) — and can retry indefinitely, so the window is reached reliably.
- PR:LPrivileges required, low
- The mgmt command needs a trusted control socket, but that capability is routinely held by the Bluetooth daemon and exposed to unprivileged session users through BlueZ Disconnect/RemoveDevice D-Bus methods, so an ordinary local user can drive the path with attacker-chosen addresses.
- UI:NUser interaction, none
- Both the mgmt command and the concurrent connection teardown are initiated programmatically by the attacker; no victim action such as pairing confirmation or opening a file is needed.
- S:UScope, unchanged
- The corruption is confined to kernel heap objects managed by the Bluetooth subsystem within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.
- C:HConfidentiality impact, high
- hci_abort_conn() dereferences the freed hci_conn (conn->hdev, conn->abort_reason, conn->handle) after it has been unlinked and released, so an attacker who reclaims the slab with controlled data obtains a read primitive over kernel memory and can leak pointers.
- I:HIntegrity impact, high
- The use-after-free is not read-only: hci_abort_conn() stores the attacker-reachable reason byte into conn->abort_reason and hci_conn_get() increments a refcount inside the freed object, giving a write primitive into reclaimed heap memory that is leverageable for control-flow hijack.
- A:HAvailability impact, high
- Dereferencing a freed or partially initialized hci_conn and then queuing abort_conn_sync on it produces slab-use-after-free oopses, refcount underflow, and kernel panics, crashing the system.