CVE-2026-90089 Bluetooth: btnxpuart: Validate the FW dump header length
A missing length check in the Linux kernel Bluetooth driver allows a truncated frame to cause an out-of-bounds read and premature controller reset, leading to denial of service.
- 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-2026-90089?
CVE-2026-90089 is a high-severity vulnerability in Linux, published on 17 Sep 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: btnxpuart: Validate the FW dump header length
nxp_process_fw_dump() pulls the ACL header off the frame and then reads seq_num and buf_len from a struct nxp_fw_dump_hdr placed at skb->data, without checking that the ACL payload is long enough to contain it.
h4_recv_buf() collects HCI_ACL_HDR_SIZE bytes of header followed by the number of payload bytes named in that header, so skb->len is 4 + dlen with dlen supplied by the controller and possibly smaller than the 8 byte dump header, or zero. A short frame with connection handle 0xfff therefore reads both fields from beyond the received data.
Beyond the read itself, buf_len is what terminates a dump: a value of zero makes the driver call hci_devcd_complete() and reset the controller, so a truncated frame can end a dump early.
Use skb_pull_data() to validate and pull the FW dump header before accessing its fields. Warn and reject the chunk if the header is truncated.
Which versions are affected by CVE-2026-90089?
How do I fix CVE-2026-90089?
Apply the vendor's patch.
Is CVE-2026-90089 being exploited?
There is no known exploitation of CVE-2026-90089 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-90089, DEBIAN-CVE-2026-90089, GHSA-h4rm-3g3v-jqmp, UBUNTU-CVE-2026-90089.