CVE-2025-40071

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

tty: n_gsm: Don't block input queue by waiting MSC

Currently gsm_queue() processes incoming frames and when opening

a DLC channel it calls gsm_dlci_open() which calls gsm_modem_update().

If basic mode is used it calls gsm_modem_upd_via_msc() and it

cannot block the input queue by waiting the response to come

into the same input queue.

Instead allow sending Modem Status Command without waiting for remote

end to respond. Define a new function gsm_modem_send_initial_msc()

for this purpose. As MSC is only valid for basic encoding, it does

not do anything for advanced or when convergence layer type 2 is used.

/// 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