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CVE-2026-53072
Bluetooth: fix locking in hci_conn_request_evt() with HCI_PROTO_DEFER
Published 2026-06-24 (4 months 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-2026-53072 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-4665-1 · 2026-07-03 · text | 6.1.176-1 | Update the kernel and reboot. DLA-4665-1 shipped the fix on 2026-07-03, in 6.1.176-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.94-1 | Update the kernel and reboot. Fixed in 6.12.94-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.0.10-1 | Update the kernel and reboot. Fixed in 7.0.10-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.10-1 | Update the kernel and reboot. Fixed in 7.0.10-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
When protocol sets HCI_PROTO_DEFER, hci_conn_request_evt() calls hci_connect_cfm(conn) without hdev->lock. Generally hci_connect_cfm() assumes it is held, and if conn is deleted concurrently -> UAF. Only SCO and ISO set HCI_PROTO_DEFER and only for defer setup listen, and HCI_EV_CONN_REQUEST is not generated for ISO. In the non-deferred listening socket code paths, hci_connect_cfm(conn) is called with hdev->lock held. Fix by holding the lock.
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_event.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
- 2026-06-24 (4 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
- 0.19%, higher than 8.6% 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 |
|---|---|---|
| 3.17 | 5.10.258 | 60e3f4ff02d1 |
| 3.17 | 5.15.209 | 9d4a6c0f43fc |
| 3.17 | 6.1.175 | c7777f534a80 |
| 3.17 | 6.6.141 | 6b4d226d01ab |
| 3.17 | 6.12.91 | 541d5bf9b5af |
| 3.17 | 6.18.33 | 385b2d0468a0 |
| 3.17 | 7.0.10 | c27224daf0b0 |
| 3.17 | 7.1 | 5c7209a341ff |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4671-1 | 2026-07-05 | bullseye 6.1.176-1~deb11u1 | tracker |
| DLA-4665-1 | 2026-07-03 | bookworm 6.1.176-1 | tracker |
| DLA-4664-1 | 2026-07-03 | bullseye 5.10.259-1 | 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 vulnerable path is reached through Bluetooth HCI connection request handling for incoming SCO/eSCO connections from a nearby Bluetooth peer, so exploitation requires adjacency to the target Bluetooth radio.
- AC:LAttack complexity, low
- The attacker can repeatedly initiate deferred SCO/eSCO connection attempts and race connection teardown/cleanup; when uncertain for this race, the higher-severity low-complexity rating is appropriate.
- PR:NPrivileges required, none
- The remote Bluetooth peer reaches the pre-authentication connection request path without local privileges or verified credentials; local deferred-listener configuration is an environmental precondition, not attacker privilege.
- UI:NUser interaction, none
- Once the target has a deferred SCO/eSCO listener, the attacker can trigger the vulnerable HCI event without requiring a victim to perform an action.
- S:UScope, unchanged
- The bug is in the kernel Bluetooth stack and impacts the same kernel security authority; it is not a VM, sandbox, or hardware boundary escape by itself.
- C:HConfidentiality impact, high
- The flaw is a use-after-free of an hci_conn object, and kernel heap UAFs can be leveraged for memory disclosure primitives in a plausible exploitation scenario.
- I:HIntegrity impact, high
- The freed hci_conn contains pointers, callback state, and protocol data used by confirmation callbacks, making control-flow or arbitrary memory corruption a defensible high-integrity impact for a kernel UAF.
- A:HAvailability impact, high
- Even without full exploitation, dereferencing a concurrently freed hci_conn can crash or destabilize the kernel, causing high availability impact.