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CVE-2026-68389
Bluetooth: hci_qca: Clear memdump state on invalid dump size
Published 2026-08-10 (2 months ago) by the Linux kernel CNA. Subsystem drivers/bluetooth. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-68389 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
qca_controller_memdump() allocates qca->qca_memdump before processing the first dump packet. For a sequence-zero packet it then disables IBS, marks memdump collection active, and reads the advertised dump size. If the controller reports a zero dump size, the error path frees the local qca_memdump object and returns without clearing qca->qca_memdump or undoing the collection state. A later memdump work item initializes its local pointer from qca->qca_memdump and skips allocation when that pointer is non-NULL, so it can operate on freed memory. The stale collection and IBS-disabled flags can also leave waiters or later transmit handling blocked behind an aborted dump. Clear the saved pointer and memdump state before returning from the invalid-size path, matching the cleanup used when hci_devcd_init() fails. A static analysis checker reported the stale memdump state, and manual source review confirmed the invalid-size failure path.
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.
drivers/bluetooth/hci_qca.c
- What this is
- QUALCOMM BLUETOOTH DRIVERMAINTAINERS section matched on drivers/bluetooth/hci_qca.c · linux-arm-msm@vger.kernel.org · Maintained
- Kernel module
- hci_uart
Check it on the machine
grep -wE 'CONFIG_BT|CONFIG_BT_HCIUART|CONFIG_BT_HCIUART_QCA' /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 hci_uartPrints 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_HCIUART, CONFIG_BT_HCIUART_QCA
- 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
- 2026-08-10 (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
- 0.25%, higher than 15.8% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- drivers/bluetooth
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.6 | 6.6.148 | 5a3945e8dea6 |
| 6.6 | 6.12.101 | 069258d5111e |
| 6.6 | 6.18.42 | cefb44c367b2 |
| 6.6 | 7.1.6 | 2363a7576947 |
| 6.6 | 7.2 | bf587a10c33e |
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:AAttack vector, adjacent network
- The vulnerable memdump packets arrive as QCA vendor HCI events (QCA_SSR_DUMP_HANDLE) emitted by the Bluetooth controller after a firmware crash/SSR, a state a nearby attacker induces or controls by attacking QCA controller firmware over the radio link, matching the CNA convention of scoring controller-event-driven Bluetooth driver bugs as Adjacent.
- AC:LAttack complexity, low
- An attacker controlling the controller-to-host HCI stream deterministically triggers the flaw by sending a sequence-0 memdump packet with dump_size 0 followed by any further memdump packet; there is no race and no attacker-uncontrollable timing or memory-layout precondition.
- PR:NPrivileges required, none
- No host credentials or authentication are needed: the memdump event is consumed unconditionally by qca_recv_event() on the driver receive path with no pairing, bonding, or capability check before qca_controller_memdump() runs.
- UI:NUser interaction, none
- SSR/memdump handling is fully automatic — qca_controller_memdump_event() queues the work item on receipt, so no local user has to open, mount, or confirm anything.
- S:UScope, unchanged
- The dangling pointer, use-after-free writes, and double free all occur in the host kernel's own heap and authority; no VM escape, IOMMU bypass, or sandbox boundary is crossed.
- C:HConfidentiality impact, high
- The stale qca->qca_memdump gives a use-after-free on a kmalloc-16 object that an attacker can reclaim with another kernel allocation, and the freed fields (received_dump/ram_dump_size) then drive hci_devcd_append() length arithmetic, yielding attacker-influenced kernel memory disclosure per UAF exploitation.
- I:HIntegrity impact, high
- The reused freed object receives attacker-supplied 32-bit values (ram_dump_size straight from the packet, plus current_seq_no/received_dump) and is later kfree()d again, providing a controlled heap write and double-free primitive usable for arbitrary write and control-flow hijack.
- A:HAvailability impact, high
- Beyond the use-after-free/double-free oops (KASAN slab-use-after-free), the uncleared QCA_MEMDUMP_COLLECTION and QCA_IBS_DISABLED flags leave wait_on_bit_timeout() waiters and the IBS transmit path stalled behind an aborted dump, persistently wedging the Bluetooth device.