Look up another CVE · open CVE-2026-74529 in the interactive tracker
CVE-2026-74529
Bluetooth: hci_sync: hold conn in hci_connect_pa_sync() callback
Published 2026-08-15 (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-2026-74529 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 | vulnerable | 6.12.113-1 | No fix published anywhere yet, neither in Debian nor upstream for the series trixie tracks. Watch the Debian tracker page for this CVE. Advisories for trixie have historically landed a median of 11 days after publication. |
| Debian 14forky | fixed | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
There is theoretical UAF if the conn is freed while the hci_sync task is running. Hold refcount to avoid that.
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
- 2026-08-15 (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
- 0.17%, higher than 6.3% 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 |
|---|---|---|
| 6.15 | 6.18.57 | 68ffe4265775 |
| 6.15 | 7.1.8 | c53c70ec289e |
| 6.15 | 7.2 | 44fc74069d89 |
| 6.12.28 | 0 | 0 |
| 6.14.6 | 0 | 0 |
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
- Reached only via local AF_BLUETOOTH BTPROTO_ISO SOCK_SEQPACKET listen() for LE broadcast PA sync (iso_listen_bis→hci_pa_create_sync→hci_connect_pa_sync); no over-the-air packet parsing triggers the bug and a remote Bluetooth peer alone cannot invoke it.
- AC:LAttack complexity, low
- Use-after-free race is attacker-controlled: a local process can listen() to start hci_le_pa_create_sync and immediately close/unlink the socket to drop the PA_LINK hci_conn while cmd_sync_work is still running, retrying until the callback dereferences freed memory.
- PR:LPrivileges required, low
- ISO sockets perform no capability checks in iso_sock_create/bt_sock_create (only init_net), so any unprivileged local user who can open AF_BLUETOOTH sockets on a BT_ISO-capable host can reach hci_connect_pa_sync without CAP_NET_ADMIN or root.
- UI:NUser interaction, none
- Exploitation requires no victim action; the attacker opens, binds, and listens on their own ISO socket and races teardown—typical on phones/headsets running LE Audio broadcast receivers with Bluetooth access granted to the attacking app/process.
- S:UScope, unchanged
- Impact stays within kernel memory via hci_conn UAF in create_pa_complete/hci_le_pa_create_sync; this is standard kernel memory corruption/privilege escalation, not a cross-boundary escape (VM, IOMMU, or sandbox).
- C:HConfidentiality impact, high
- UAF of struct hci_conn lets an attacker influence freed slab contents and read adjacent kernel data through hci_conn_valid(), conn->flags, and conn->iso_qos dereferences during async PA sync work and error callbacks.
- I:HIntegrity impact, high
- Freed hci_conn is written via set_bit/clear_bit on conn->flags and error-path hci_connect_cfm()/hci_conn_add_unset in create_pa_complete; heap grooming of the reclaimed allocation enables arbitrary kernel writes and control-flow hijack.
- A:HAvailability impact, high
- Dereferencing or deleting a freed hci_conn in hci_cmd_sync_work reliably causes kernel memory corruption, oops, or panic; UAFs in this subsystem have been observed to crash the host even when not fully exploited for privilege escalation.