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…
Overview
CVE-2025-40308 is a known-severity vulnerability. It was published on December 8, 2025.
Technical 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
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
References
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Frequently asked questions
What is CVE-2025-40308?
CVE-2025-40308 is a known-severity vulnerability. It was published on December 8, 2025.
How severe is CVE-2025-40308?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2025-40308?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-40308?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2025-40308 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.