Php Version 5640 Vulnerabilities Link ((install)) -

: An out-of-bounds read error in the xmlrpc_decode function. Remote attackers could cause memory corruption or information disclosure via a hostile XML-RPC server.

As of 2026, running PHP 5.6.40 poses extreme risks to production environments: PHP Requirements - Knowledgebase - The Events Calendar php version 5640 vulnerabilities link

Using an EOL version like 5.6.40 exposes servers to significant risks because: PHP Remote Code Execution Vulnerability (CVE-2019-11043) : An out-of-bounds read error in the xmlrpc_decode function