CVE-2026-90256

8.8 HIGH

Published 2026-09-17 · Updated 2026-09-18

AI risk analysis

Summary: This vulnerability allows for a use-after-free condition in the Linux kernel's Bluetooth L2CAP implementation, which could lead to a denial of service or potentially other issues if exploited.
Exploitability: Exploitation requires concurrent deletion of a l2cap_conn while accessing hci_conn::l2cap_data, making it moderately difficult to exploit.
Blast radius: If exploited, this could result in a denial of service for Bluetooth services on affected systems.
Detection: No reliable host or network indicator is derivable from the published description.
Prioritized remediation: Upgrade to the fixed version 5.19-rc1 or later.

dosbluetoothkernel

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: use proto_lock for l2cap_data to fix l2cap_disconn_ind hci_conn::l2cap_data is accessed without locks in l2cap_disconn_ind via hci_conn_timeout (disc_work) -> hci_proto_disconn_ind -> l2cap_disconn_ind. This is UAF if the l2cap_conn is deleted concurrently. disc_work is disabled sync in hci_conn_del(), so we cannot take hci_dev_lock in disc_work. Fix by using proto_lock to guard l2cap_data, in addition to hdev->lock which is held in other access paths.

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

All references

Source data: NVD (nvd.nist.gov), public domain. Exploit-DB.ai adds local AI analysis for defensive use only.

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