CVE-2025-37918: Bluetooth: btusb: avoid NULL pointer dereference in skb_dequeue()
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.
Classification
CVE ID: CVE-2025-37918
Affected Products
Vendor: Linux
Product: Linux
Exploit Prediction Scoring System (EPSS)
EPSS Score: 0.02% (probability of being exploited)
EPSS Percentile: 4.6% (scored less or equal to compared to others)
EPSS Date: 2025-06-18 (when was this score calculated)
References
https://nvd.nist.gov/vuln/detail/CVE-2025-37918https://git.kernel.org/stable/c/2e8d44ebaa7babdd5c5ab50ca275826e241920d6
https://git.kernel.org/stable/c/b70b41591ec48c78ec6a885e1f57bfc4029e5e13
https://git.kernel.org/stable/c/8563d9fabd8a4b726ba7acab4737c438bf11a059
https://git.kernel.org/stable/c/0317b033abcd1d8dd2798f0e2de5e84543d0bd22