CVE-2025-68304: In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_core: lookup hci_conn on RX path on protocol side The hdev lock/l...

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_core: lookup hci_conn on RX path on protocol side The hdev lock/lookup/unlock/use pattern in the packet RX path doesn't ensure hci_conn* is not concurrently modified/deleted. This locking appears to be leftover from before conn_hash started using RCU commit bf4c63252490b ("Bluetooth: convert conn hash to RCU") and not clear if it had purpose since then. Currently, there are code paths that delete hci_conn* from elsewhere than the ordered hdev->workqueue where the RX work runs in. E.g. commit 5af1f84ed13a ("Bluetooth: hci_sync: Fix UAF on hci_abort_conn_sync") introduced some of these, and there probably were a few others before it. It's better to do the locking so that even if these run concurrently no UAF is possible. Move the lookup of hci_conn and associated socket-specific conn to protocol recv handlers, and do them within a single critical section to cover hci_conn* usage and lookup. syzkaller has reported a crash that appears to be this issue: [Task hdev->workqueue] [Task 2] hci_disconnect_all_sync l2cap_recv_acldata(hcon) hci_conn_get(hcon) hci_abort_conn_sync(hcon) hci_dev_lock hci_dev_lock hci_conn_del(hcon) v-------------------------------- hci_dev_unlock hci_conn_put(hcon) conn = hcon->l2cap_data (UAF)

Metrics

EPSS Probability

0.14%

4.1th percentile

Probability of exploitation in the next 30 days. Learn more

References

Timeline

Published: Dec 16, 2025
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2025-68304?

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_core: lookup hci_conn on RX path on protocol side The hdev lock/lookup/unlock/use pattern in the packet RX path doesn't ensure hci_conn* is not concurrently modified/deleted. This locking appears to be leftover from before conn_hash started using RCU commit bf4c63252490b ("Bluetooth: convert conn hash to RCU") and not clear if it had purpose since then. Currently, there are code paths that delete hci_conn* from elsewhere than the ordered hdev->workqueue where the RX work runs in. E.g. commit 5af1f84ed13a ("Bluetooth: hci_sync: Fix UAF on hci_abort_conn_sync") introduced some of these, and there probably were a few others before it. It's better to do the locking so that even if these run concurrently no UAF is possible. Move the lookup of hci_conn and associated socket-specific conn to protocol recv handlers, and do them within a single critical section to cover hci_conn* usage and lookup. syzkaller has reported a crash that appears to be this issue: [Task hdev->workqueue] [Task 2] hci_disconnect_all_sync l2cap_recv_acldata(hcon) hci_conn_get(hcon) hci_abort_conn_sync(hcon) hci_dev_lock hci_dev_lock hci_conn_del(hcon) v-------------------------------- hci_dev_unlock hci_conn_put(hcon) conn = hcon->l2cap_data (UAF)

How severe is CVE-2025-68304?

Severity scoring for CVE-2025-68304 is pending analysis. The EPSS model estimates a 0.14% probability of exploitation in the next 30 days.

How do I fix CVE-2025-68304?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.