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.
Published: 2025-12-08
Score: 7.0 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-4404-1 linux security update
Debian DLA Debian DLA DLA-4436-1 linux-6.1 security update
Ubuntu USN Ubuntu USN USN-8029-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8030-1 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-8029-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8048-1 Linux kernel (OEM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8029-3 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8095-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8096-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8095-2 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8096-2 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8100-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-8095-3 Linux kernel (Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-8096-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8096-4 Linux kernel (Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-8095-4 Linux kernel (AWS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8096-5 Linux kernel (NVIDIA Tegra IGX) vulnerabilities
Ubuntu USN Ubuntu USN USN-8116-1 Linux kernel (Intel IoTG Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-8125-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8126-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8095-5 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-8141-1 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-8163-1 Linux kernel (Azure FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8165-1 Linux kernel (Azure FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8163-2 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8243-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8261-1 Linux kernel (Xilinx) vulnerabilities
History

Tue, 09 Dec 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate


Mon, 08 Dec 2025 01:15:00 +0000

Type Values Removed Values Added
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.
Title Bluetooth: bcsp: receive data only if registered
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-11T21:46:50.565Z

Reserved: 2025-04-16T07:20:57.185Z

Link: CVE-2025-40308

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2025-12-08T01:16:03.073

Modified: 2026-04-15T00:35:42.020

Link: CVE-2025-40308

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-12-08T00:00:00Z

Links: CVE-2025-40308 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.