High [CVE-2026-63944] fix UAF in hci_le_create_cis_sync
This high-severity Red Hat Linux advisory covers CVE-2026-63944 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat package: kernel.
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Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync hci_le_create_cis_sync() dereferences conn->conn_timeout after releasing both rcu_read_lock() and hci_dev_lock(hdev).
The conn pointer was obtained from an RCU-protected iteration over hdev->conn_hash.list and is not valid once these locks are dropped. A concurrent disconnect can free the hci_conn between the unlock and the dereference, causing a use-after-free read.
The cancellation mechanism in hci_conn_del() cannot prevent this because hci_le_create_cis_pending() queues hci_create_cis_sync with data=NULL: hci_cmd_sync_queue(hdev, hci_create_cis_sync, NULL, NULL); While hci_conn_del() dequeues with data=conn: hci_cmd_sync_dequeue(hdev, NULL, conn, NULL); Since NULL!= conn, the lookup in _hci_cmd_sync_lookup_entry() never matches, and the pending work item is not cancelled.
Fix this by saving conn->conn_timeout into a local variable while the locks are still held, so the stale conn pointer is never dereferenced after unlock. This is the same class of bug as the one fixed by commit 035c25007c9e ("Bluetooth: hci_sync: Fix UAF on le_read_features_complete") which addressed the identical pattern in a different function.
This vulnerability was identified using 0sec.ai, an open-source automated security auditing platform ( ).
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · high-confidence parse· fetched 7 days ago·verify at source
- kernel-0:6.12.0-211.53.1.el10_2
- kernel-0:5.14.0-687.47.1.el9_8
- RHSA-2026:65334
- RHSA-2026:67150
Official advisory · high-confidence parse· fetched 7 days ago·verify at source
Mitigation
Upgrade to a fixed release: kernel-0:6.12.0-211.53.1.el10_2, kernel-0:5.14.0-687.47.1.el9_8, RHSA-2026:65334, RHSA-2026:67150. That is the remediation for this advisory.
The vendor advisory may list interim mitigations or workarounds not captured here. Review it before change work.
Official advisory · high-confidence parse· fetched 7 days ago·verify at source
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