CVE-2026-31771 PUBLISHED

Bluetooth: hci_event: move wake reason storage into validated event handlers

Assigner: Linux
Reserved: 09.03.2026 Published: 01.05.2026 Updated: 01.05.2026

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

Bluetooth: hci_event: move wake reason storage into validated event handlers

hci_store_wake_reason() is called from hci_event_packet() immediately after stripping the HCI event header but before hci_event_func() enforces the per-event minimum payload length from hci_ev_table. This means a short HCI event frame can reach bacpy() before any bounds check runs.

Rather than duplicating skb parsing and per-event length checks inside hci_store_wake_reason(), move wake-address storage into the individual event handlers after their existing event-length validation has succeeded. Convert hci_store_wake_reason() into a small helper that only stores an already-validated bdaddr while the caller holds hci_dev_lock(). Use the same helper after hci_event_func() with a NULL address to preserve the existing unexpected-wake fallback semantics when no validated event handler records a wake address.

Annotate the helper with __must_hold(&hdev->lock) and add lockdep_assert_held(&hdev->lock) so future call paths keep the lock contract explicit.

Call the helper from hci_conn_request_evt(), hci_conn_complete_evt(), hci_sync_conn_complete_evt(), le_conn_complete_evt(), hci_le_adv_report_evt(), hci_le_ext_adv_report_evt(), hci_le_direct_adv_report_evt(), hci_le_pa_sync_established_evt(), and hci_le_past_received_evt().

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from 2f20216c1d6fe17c1a224f658be0dc6fab2269c7 to 86c8d07a64d553c41e213b52650020010f9ef23e (excl.)
  • affected from 2f20216c1d6fe17c1a224f658be0dc6fab2269c7 to 2b2bf47cd75518c36fa2d41380e4a40641cc89cd (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 5.10 is affected
  • unaffected from 0 to 5.10 (excl.)
  • unaffected from 6.19.12 to 6.19.* (incl.)
  • unaffected from 7.0 to * (incl.)

References