Linux Kernel Null Pointer Dereference Vulnerability in tty n_gsm Component

A null pointer dereference vulnerability has been identified in the Linux kernel's tty n_gsm component. This issue arises in the gsmld_receive_buf() function, which can be accessed without initializing the MUX, leading to a dereference of a null pointer when calling gsm->receive(). The vulnerability exists because the code assumes gsm->receive() is only called after MUX activation.

Impact

Exploitation of this vulnerability leads to a null pointer dereference, causing a crash or undefined behavior in the kernel.

Remediation

The vulnerability has been addressed in the official Linux kernel repository. Users should upgrade to the latest version where this issue has been fixed.