CVE-2025-40071
kernel: tty: n_gsm: Don't block input queue by waiting MSC
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · October 28, 2025
Updated · June 30, 2026
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.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 6.1CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H
CWE-1322 · Use of Blocking Code in Single-threaded, Non-blocking Context