CVE-2026-98739

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: RFCOMM: Fix initial port reference race

For RFCOMM_RELEASE_ONHUP devices, rfcomm_tty_install() and

__rfcomm_release_dev() both use RFCOMM_TTY_OWNED to decide who drops the

initial tty_port reference. The release path tests the bit separately

from the install path setting it, so both can drop that reference.

The synchronous hangup does not prevent this race: port->tty is not

assigned until tty_port_open(), after installation. The following

interleaving is possible:

1. Install and release each obtain a reference with rfcomm_dev_get().

2. Release observes RFCOMM_TTY_OWNED clear.

3. Install sets RFCOMM_TTY_OWNED and drops the initial reference.

4. Release drops the same initial reference again.

5. TTY cleanup drops its reference and frees the device.

6. Release performs its final tty_port_put() on the freed port.

KASAN reported:

BUG: KASAN: slab-use-after-free in tty_port_put+0x22/0x190

Wri

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References