CVE-2025-37918 Bluetooth: btusb: avoid NULL pointer dereference in skb_dequeue()

What is CVE-2025-37918?

CVE-2025-37918 is a high-severity vulnerability in Linux kernel, published on 20 May 2025. 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: btusb: avoid NULL pointer dereference in skb_dequeue()

A NULL pointer dereference can occur in skb_dequeue() when processing a QCA firmware crash dump on WCN7851 (0489:e0f3).

[ 93.672166] Bluetooth: hci0: ACL memdump size(589824)

[ 93.672475] BUG: kernel NULL pointer dereference, address: 0000000000000008 [ 93.672517] Workqueue: hci0 hci_devcd_rx [bluetooth] [ 93.672598] RIP: 0010:skb_dequeue+0x50/0x80

The issue stems from handle_dump_pkt_qca() returning 0 even when a dump packet is successfully processed. This is because it incorrectly forwards the return value of hci_devcd_init() (which returns 0 on success). As a result, the caller (btusb_recv_acl_qca() or btusb_recv_evt_qca()) assumes the packet was not handled and passes it to hci_recv_frame(), leading to premature kfree() of the skb.

Later, hci_devcd_rx() attempts to dequeue the same skb from the dump queue, resulting in a NULL pointer dereference.

Fix this by: 1. Making handle_dump_pkt_qca() return 0 on success and negative errno on failure, consistent with kernel conventions. 2. Splitting dump packet detection into separate functions for ACL and event packets for better structure and readability.

This ensures dump packets are properly identified and consumed, avoiding double handling and preventing NULL pointer access.

Weakness: CWE-476

Which versions are affected by CVE-2025-37918?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2025-37918?

Apply the vendor's patch.

Is CVE-2025-37918 being exploited?

There is no known exploitation of CVE-2025-37918 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2025-37918, DEBIAN-CVE-2025-37918, GHSA-qjmq-chg2-32xr, ROOT-OS-UBUNTU-2404-CVE-2025-37918, UBUNTU-CVE-2025-37918.