CVE-2024-26903

CVE Details

Release Date:

2024-04-17

Description

In the Linux kernel, the following vulnerability has been resolved:\nBluetooth: rfcomm: Fix null-ptr-deref in rfcomm_check_security\nDuring our fuzz testing of the connection and disconnection process at the\nRFCOMM layer, we discovered this bug. By comparing the packets from a\nnormal connection and disconnection process with the testcase that\ntriggered a KASAN report. We analyzed the cause of this bug as follows:\n1. In the packets captured during a normal connection, the host sends a\n`Read Encryption Key Size` type of `HCI_CMD` packet\n(Command Opcode: 0x1408) to the controller to inquire the length of\nencryption key.After receiving this packet, the controller immediately\nreplies with a Command Completepacket (Event Code: 0x0e) to return the\nEncryption Key Size.\n2. In our fuzz test case, the timing of the controller's response to this\npacket was delayed to an unexpected point: after the RFCOMM and L2CAP\nlayers had disconnected but before the HCI layer had disconnected.\n3. After receiving the Encryption Key Size Response at the time described\nin point 2, the host still called the rfcomm_check_security function.\nHowever, by this time `struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;`\nhad already been released, and when the function executed\n`return hci_conn_security(conn->hcon, d->sec_level, auth_type, d->out);`,\nspecifically when accessing `conn->hcon`, a null-ptr-deref error occurred.\nTo fix this bug, check if `sk->sk_state` is BT_CLOSED before calling\nrfcomm_recv_frame in rfcomm_process_rx.

See more information about CVE-2024-26903 from MITRE CVE dictionary and NIST NVD

CVSS Scoring

NOTE: The following CVSS v3.1 metrics and score provided are preliminary and subject to review.

Base Score:	5.5	CVSS Vector:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector:	Local network	Attack Complexity:	Low
Privileges Required:	Low	User Interaction:	None
Scope:	Unchanged	Confidentiality Impact:	None
Integrity Impact:	None	Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 6 (kernel-uek)	ELSA-2024-12606	2024-09-02
Oracle Linux version 7 (kernel-uek)	ELSA-2024-12606	2024-09-02
Oracle VM version 3 (kernel-uek)	OVMSA-2024-0011	2024-09-03