CVE-2024-26903

Technical Description

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

Bluetooth: rfcomm: Fix null-ptr-deref in rfcomm_check_security

During our fuzz testing of the connection and disconnection process at the

RFCOMM layer, we discovered this bug. By comparing the packets from a

normal connection and disconnection process with the testcase that

triggered a KASAN report. We analyzed the cause of this bug as follows:

1. In the packets captured during a normal connection, the host sends a

`Read Encryption Key Size` type of `HCI_CMD` packet

(Command Opcode: 0x1408) to the controller to inquire the length of

encryption key.After receiving this packet, the controller immediately

replies with a Command Completepacket (Event Code: 0x0e) to return the

Encryption Key Size.

2. In our fuzz test case, the timing of the controller's response to this

packet was delayed to an unexpected point: after the RFCOMM and L2CAP

layers had disconnected but before the HCI layer had disconnected.

3. After recei

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. 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.

Affected Products

References