CVE-2025-40308: In the Linux kernel, the following vulnerability has been resolved: Bluetooth: bcsp: receive data only if registered Currently, bcsp_recv() can be c...

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: bcsp: receive data only if registered Currently, bcsp_recv() can be called even when the BCSP protocol has not been registered. This leads to a NULL pointer dereference, as shown in the following stack trace: KASAN: null-ptr-deref in range [0x0000000000000108-0x000000000000010f] RIP: 0010:bcsp_recv+0x13d/0x1740 drivers/bluetooth/hci_bcsp.c:590 Call Trace: <TASK> hci_uart_tty_receive+0x194/0x220 drivers/bluetooth/hci_ldisc.c:627 tiocsti+0x23c/0x2c0 drivers/tty/tty_io.c:2290 tty_ioctl+0x626/0xde0 drivers/tty/tty_io.c:2706 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f To prevent this, ensure that the HCI_UART_REGISTERED flag is set before processing received data. If the protocol is not registered, return -EUNATCH.

Metrics

EPSS Probability

0.17%

6.0th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 48effdb7a798232db945503cf3f51e0be8070cea, < 39a7d40314b6288cfa2d13269275e9247a7a055a; >= 45fa7bd82c6178f4fec0ab94891144a043ec5fe8, < 164586725b47f9d61912e6bf17dbaffeff11710b; >= d71a57a34ab6bbc95dc461158403c02e8ff3f912, < b65ca9708bfbf47d8b7bd44b7c574bd16798e9c9; >= 9cf7dccaa7f4c56d2089700e5cb11f85a8d5f6cf, < 8b892dbef3887dbe9afdc7176d1a5fd90e1636aa; >= 806464634e7fc6b523160defeeddb1ade2a72f81, < 799cd62cbcc3f12ee04b33ef390ff7d41c37d671; >= 6b7a32fa9bacdebd98c18b2a56994116995ee643, < b420a4c7f915fc1c94ad1f6ca740acc046d94334; >= 366ceff495f902182d42b6f41525c2474caf3f9a, < 55c1519fca830f59a10bbf9aa8209c87b06cf7bc; >= 366ceff495f902182d42b6f41525c2474caf3f9a, < ca94b2b036c22556c3a66f1b80f490882deef7a6; 15543b7bbe7b5f744fdbb44f75b14f81a0117813; a4b89a45b12b69bc82c8137346b150a118e02c26; >= 5.4.293, < 5.4.302; >= 5.10.237, < 5.10.247; >= 5.15.181, < 5.15.197; >= 6.1.135, < 6.1.159; >= 6.6.88, < 6.6.117; >= 6.12.24, < 6.12.58; >= 6.13.12, < 6.14; >= 6.14.3, < 6.15
Linux	Linux	6.15

References

Timeline

Published: Dec 8, 2025
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2025-40308?

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: bcsp: receive data only if registered Currently, bcsp_recv() can be called even when the BCSP protocol has not been registered. This leads to a NULL pointer dereference, as shown in the following stack trace: KASAN: null-ptr-deref in range [0x0000000000000108-0x000000000000010f] RIP: 0010:bcsp_recv+0x13d/0x1740 drivers/bluetooth/hci_bcsp.c:590 Call Trace: <TASK> hci_uart_tty_receive+0x194/0x220 drivers/bluetooth/hci_ldisc.c:627 tiocsti+0x23c/0x2c0 drivers/tty/tty_io.c:2290 tty_ioctl+0x626/0xde0 drivers/tty/tty_io.c:2706 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f To prevent this, ensure that the HCI_UART_REGISTERED flag is set before processing received data. If the protocol is not registered, return -EUNATCH.

How severe is CVE-2025-40308?

Severity scoring for CVE-2025-40308 is pending analysis. The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.

How do I fix CVE-2025-40308?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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