High 8.8Published Jul 19, 2026

CVE-2026-63944Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync

Updated under an hour ago (Oct 28, 2026, 9:30 PM ET)

Does this affect you?

It affects Linux and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for Linux

Exploited in the last 30 days

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).

CVSS: 8.8 HIGH (v3.1, CNA)CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-416
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Analyzed
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from c09b80be6ffc338634b2f5f8cfa12b6843410834 before a55618c0f4cead9e59c63f5ee030d393fd70d861; from c09b80be6ffc338634b2f5f8cfa12b6843410834 before a921957d39290143629eb38c4f74b9bef8035d0a; from c09b80be6ffc338634b2f5f8cfa12b6843410834 before d9019210c8c30d40eb20094274cc647e352f48f7; from c09b80be6ffc338634b2f5f8cfa12b6843410834 before 380e67b1794a9a281a0cb592b4e62077fbd0c8ca; from c09b80be6ffc338634b2f5f8cfa12b6843410834 before bfea6091e0fffb270c20e74384b660910277eb6c	CNA record
linux linux_kernel linux:linux_kernel	from 6.4 before 6.6.143; from 6.7 before 6.12.93; from 6.13 before 6.18.35; from 6.19 before 7.0.12; 7.1; 7.1; 7.1; 7.1; and 1 more ranges	NVD

References

References

https://git.kernel.org/stable/c/a55618c0f4cead9e59c63f5ee030d393fd70d861	patch
https://git.kernel.org/stable/c/a921957d39290143629eb38c4f74b9bef8035d0a	patch
https://git.kernel.org/stable/c/d9019210c8c30d40eb20094274cc647e352f48f7	patch
https://git.kernel.org/stable/c/380e67b1794a9a281a0cb592b4e62077fbd0c8ca	patch
https://git.kernel.org/stable/c/bfea6091e0fffb270c20e74384b660910277eb6c	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.