In Kamailio before 5.0.7 and 5.1.x before 5.1.4, a crafted SIP message with an invalid Via header causes a segmentation fault and crashes Kamailio. The reason is missing input validation in the crcitt_string_array core function for calculating a CRC hash for To tags. (An additional error is present in the check_via_address core function: this function also misses input validation.) This could result in denial of service and potentially the execution of arbitrary code.

In Kamailio before 5.0.7 and 5.1.x before 5.1.4, a crafted SIP message with a double "To" header and an empty "To" tag causes a segmentation fault and crash. The reason is missing input validation in the "build_res_buf_from_sip_req" core function. This could result in denial of service and potentially the execution of arbitrary code.