CVE-2026-46138 Bluetooth: hci_event: Fix OOB read and infinite loop in hci_le_create_big_complete_evt
A missing bounds check in the Linux kernel Bluetooth driver allows a malicious controller to trigger an out-of-bounds read and infinite loop, causing a system hang.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46138?
CVE-2026-46138 is a high-severity denial of service vulnerability in Linux kernel, published on 28 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_event: Fix OOB read and infinite loop in hci_le_create_big_complete_evt
hci_le_create_big_complete_evt() iterates over BT_BOUND connections for a BIG handle using a while loop, accessing ev->bis_handle[i++] on each iteration. However, there is no check that i stays within ev->num_bis before the array access.
When a controller sends a LE_Create_BIG_Complete event with fewer bis_handle entries than there are BT_BOUND connections for that BIG, or with num_bis=0, the loop reads beyond the valid bis_handle[] flex array into adjacent heap memory. Since the out-of-bounds values typically exceed HCI_CONN_HANDLE_MAX (0x0EFF), hci_conn_set_handle() rejects them and the connection remains in BT_BOUND state. The same connection is then found again by hci_conn_hash_lookup_big_state(), creating an infinite loop with hci_dev_lock held.
Fix this by terminating the BIG if in case not all BIS could be setup properly.
Weakness: CWE-125
Which versions are affected by CVE-2026-46138?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46138?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-46138 being exploited?
There is no known exploitation of CVE-2026-46138 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-89130, BELL-CVE-2026-46138, DEBIAN-CVE-2026-46138, GHSA-wf79-2h53-8gvp, ROOT-OS-UBUNTU-2404-CVE-2026-46138, UBUNTU-CVE-2026-46138.