Answer in brief
CVE-2026-63944 records a High severity (CVSS 8.8) vulnerability in Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=c09b80be6ffc338634b2f5f8cfa12b6843410834 <a55618c0f4cead9e59c63f5ee030d393fd70d861 || >=c09b80be6ffc338634b2f5f8cfa12b6843410834 <a921957d39290143629eb38c4f74b9bef8035d0a || >=c09b80be6ffc338634b2f5f8cfa12b6843410834 <d9019210c8c30d40eb20094274cc647e352f48f7 || >=c09b80be6ffc338634b2f5f8cfa12b6843410834 <380e67b1794a9a281a0cb592b4e62077fbd0c8ca || >=c09b80be6ffc338634b2f5f8cfa12b6843410834 <bfea6091e0fffb270c20e74384b660910277eb6c | a55618c0f4cead9e59c63f5ee030d393fd70d861, a921957d39290143629eb38c4f74b9bef8035d0a, d9019210c8c30d40eb20094274cc647e352f48f7, 380e67b1794a9a281a0cb592b4e62077fbd0c8ca, bfea6091e0fffb270c20e74384b660910277eb6c |
| Linux/Linuxgeneric | 6.4 | Not reported |
Published upstream
Jul 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 26, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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 (https://github.com/0sec-labs).
Quoted source text, attributed separately from HOL analysis.