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.
References8
- git.kernel.org/stable/c/0e1fc7cab95ad958e55d70a5dfaaea687c9c639f
- git.kernel.org/stable/c/1074bcc57f741223f9fa82ce6afe5c3d783e4d10
- git.kernel.org/stable/c/4ef05db5b08b176a551b4a6287372045998806b0
- git.kernel.org/stable/c/564ae0e05e598aa895b9dbd18cb7d6eb64752869
- git.kernel.org/stable/c/5d5a625cbc854d4c4f68e4b16fcf6e682d9a9ed1
- git.kernel.org/stable/c/6cb79e6499228cfdbd4b3301371ce74d01cd2f80
- git.kernel.org/stable/c/aab17938998b29e75c3324763411aef3e300fc67
- git.kernel.org/stable/c/ad0f44a3f1f688558ed876a0702bc2c82b0df689
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 15 · as of 9 November 2026
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