CVE-2026-98108

/// Technical description

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

Bluetooth: L2CAP: fix chan mode for LE_CONN_REQ + EXT_FLOWCTL pchan

l2cap_new_connection() sets default value of channel mode to match the

parent channel. l2cap_le_connect_req() left this at the default, and

created L2CAP_MODE_EXT_FLOWCTL channels if listening pchan has that

mode. This causes FLAG_DEFER_SETUP channels to reply to

L2CAP_LE_CONN_REQ with L2CAP_ECRED_CONN_RSP, which is incorrect.

It can also result to stack OOB write (of l2cap_alloc_cid determined

values) in l2cap_ecred_rsp_defer(), as l2cap_le_connect_req() does not

limit maximum number of deferred channels or check for duplicate ident.

Fix by setting chan->mode correctly in l2cap_le_connect_req().

Also check channel mode in l2cap_ecred_rsp_defer(), and do WARN_ON_ONCE

instead of OOB write to make it less brittle.

/// 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