Function iconv_mime_decode_headers() 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.
https://www.debian.org/security/2019/dsa-4529
https://www.debian.org/security/2019/dsa-4527
https://seclists.org/bugtraq/2019/Sep/38
https://seclists.org/bugtraq/2019/Sep/35
https://bugs.php.net/bug.php?id=78069
https://access.redhat.com/errata/RHSA-2019:3299
https://access.redhat.com/errata/RHSA-2019:2519
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00029.html