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 crcittstringarray core function for calculating a CRC hash for To tags. (An additional error is present in the checkviaaddress 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 "buildresbuffromsipreq" core function. This could result in denial of service and potentially the execution of arbitrary code.