A buffer overflow vulnerability exists in all versions of sngrep since v0.4.2, due to improper handling of 'Call-ID' and 'X-Call-ID' SIP headers. The functions sip_get_callid and sip_get_xcallid in sip.c use the strncpy function to copy header contents into fixed-size buffers without checking the data length. This flaw allows remote attackers to execute arbitrary code or cause a denial of service (DoS) through specially crafted SIP messages.