CVE-2026-98461 Bluetooth: hci_sock: validate event length before filtering
A local attacker with Bluetooth access can trigger an out-of-bounds read in the Linux kernel by sending malformed HCI events, potentially causing a crash or leaking memory.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98461?
CVE-2026-98461 is a memory corruption vulnerability in Linux, published on 18 Oct 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_sock: validate event length before filtering
is_filtered_packet() reads the event code from skb->data[0] without first checking that the skb is nonempty. When an opcode filter is configured, it also reads the command opcode at offsets 3 or 4 without checking that a Command Complete or Command Status event is long enough.
hci_send_to_sock() invokes the filter before hci_event_packet() validates the event header. A malformed event supplied by a controller or a vhci device can therefore cause an out-of-bounds read.
Keep the unmasked event code for the opcode checks. The masked value is needed for the 64-bit event bitmap, but using it to identify command events aliases event codes above 0x3f. In particular, Synchronous Train Complete (0x4f) was treated as Command Status (0x0f) even though its payload has no opcode.
Reject actual command events that are too short for the field being inspected. A truncated command event cannot match a configured opcode.
Which versions are affected by CVE-2026-98461?
How do I fix CVE-2026-98461?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-98461 being exploited?
There is no known exploitation of CVE-2026-98461 in the wild and no public exploit code.
Sources
Also known as AZL-109364, BELL-CVE-2026-98461, DEBIAN-CVE-2026-98461, GHSA-xggg-9q4f-8rr9, UBUNTU-CVE-2026-98461.