Disable n_gsm module
The n_gsm module appears to suffer from various security relevant issues:
Attaching N_GSM0710 ldisc requires CAP_NET_ADMIN since kernel 6.6, and that change has now also been backported to older kernel release branches, but Greg Kroah-Hartman still recommends disabling CONFIG_N_GSM at build time:
https://www.openwall.com/lists/oss-security/2024/04/17/1
It seems wise to follow his recommendation.
Also tagging @anthraxx because this is also relevant for linux-hardened.
Edited by Pascal Ernster