CVE-2025-40308 Details
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.
A NULL pointer dereference vulnerability has been identified in the Linux kernel's Bluetooth BCSP protocol handling. The issue arises in the 'bcsp_recv()' function, which can be invoked even when the BCSP protocol is not registered. This oversight leads to a NULL pointer dereference, as indicated by a KASAN (Kernel Address Sanitizer) report. The vulnerability is present in the Linux kernel stable tree.
The vulnerability has been addressed in the Linux kernel. Users should upgrade to the latest version where this issue has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Dec 8, 2025References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/164586725b47f9d61912e6bf17dbaffeff11710b | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/39a7d40314b6288cfa2d13269275e9247a7a055a | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/55c1519fca830f59a10bbf9aa8209c87b06cf7bc | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/799cd62cbcc3f12ee04b33ef390ff7d41c37d671 | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/8b892dbef3887dbe9afdc7176d1a5fd90e1636aa | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/b420a4c7f915fc1c94ad1f6ca740acc046d94334 | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/b65ca9708bfbf47d8b7bd44b7c574bd16798e9c9 | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/ca94b2b036c22556c3a66f1b80f490882deef7a6 | kernel.org | Source CodeVendor |
Weakness Enumeration
No weakness enumeration is available for this CVE.
Affected Products
| Product | Versions |
|---|---|
| Linux kernel | All versions |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | kernel.org |
| Dec 8, 2025 | New CVE Received | kernel.org |