CVE-2026-90256: Bluetooth: L2CAP: use proto_lock for l2cap_data to fix l2cap_disconn_ind

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-17 · updated 2026-10-21

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.

Affected products

Linux kernel: from 6.6.84 before 6.6.160; from 6.12.20 before 6.12.114; from 6.13.8 before 6.14; 6.14 — fixed in 6.12.114, 6.14, 6.6.160, 7.3

How to fix

Upgrade to a fixed version: Linux kernel 6.12.114, 6.14, 6.6.160, 7.3. Check the vendor advisory for mitigations.

References

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