CVE-2026-43019 Bluetooth: hci_conn: fix potential UAF in set_cig_params_sync
A use-after-free vulnerability in the Linux kernel Bluetooth subsystem allows attackers to execute arbitrary code or escalate privileges via concurrent connection handling.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-43019?
CVE-2026-43019 is a high-severity use after free vulnerability in Linux kernel, published on 1 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_conn: fix potential UAF in set_cig_params_sync
hci_conn lookup and field access must be covered by hdev lock in set_cig_params_sync, otherwise it's possible it is freed concurrently.
Take hdev lock to prevent hci_conn from being deleted or modified concurrently. Just RCU lock is not suitable here, as we also want to avoid "tearing" in the configuration.
Which versions are affected by CVE-2026-43019?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43019?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-43019 being exploited?
There is no known exploitation of CVE-2026-43019 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-85398, BELL-CVE-2026-43019, DEBIAN-CVE-2026-43019, GHSA-2qwp-9c8h-mrvc, ROOT-OS-UBUNTU-2404-CVE-2026-43019, UBUNTU-CVE-2026-43019.