The telnet_input_char function in opt/src/accel-pppd/cli/telnet.c suffers from a memory corruption vulnerability, whereby user input cmdline_len is copied into a fixed buffer b->buf without any bound checks. If the server connects with a malicious client, crafted client requests can remotely trigger this vulnerability.
CWE-787 - Out-of-Bounds Write
Out-of-bounds write vulnerability is a memory access bug that allows software to write data past the end or before the beginning of the intended buffer. This may result in the corruption of data, a crash, or arbitrary code execution.