php: Out-of-bounds read due to integer overflow in iconv_mime_decode_headers()

Function iconvmimedecodeheaders in PHP versions 7.1.x below 7.1.30, 7.2.x below 7.2.19 and 7.3.x below 7.3.6 may perform out-of-buffer read due to integer overflow when parsing MIME headers. This may lead to information disclosure or crash...