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In the Linux kernel, the following vulnerability has been...

Moderate severity Unreviewed Published Apr 17, 2024 to the GitHub Advisory Database • Updated May 9, 2024

Package

No package listedSuggest a package

Affected versions

Unknown

Patched versions

Unknown

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 receiving the Encryption Key Size Response at the time described
    in point 2, the host still called the rfcomm_check_security function.
    However, by this time struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;
    had already been released, and when the function executed
    return hci_conn_security(conn->hcon, d->sec_level, auth_type, d->out);,
    specifically when accessing conn->hcon, a null-ptr-deref error occurred.

To fix this bug, check if sk->sk_state is BT_CLOSED before calling
rfcomm_recv_frame in rfcomm_process_rx.

References

Published by the National Vulnerability Database Apr 17, 2024
Published to the GitHub Advisory Database Apr 17, 2024
Last updated May 9, 2024

Severity

Moderate
5.5
/ 10

CVSS base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weaknesses

CVE ID

CVE-2024-26903

GHSA ID

GHSA-w69g-9g23-pfwc

Source code

No known source code

Dependabot alerts are not supported on this advisory because it does not have a package from a supported ecosystem with an affected and fixed version.

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