An integer overflow vulnerability existed in the static function wolfssladdtochain, that caused heap corruption when certificate data was written out of bounds of an insufficiently sized certificate buffer. wolfssladdtochain is called by these API: wolfSSLCTXaddextrachaincert, wolfSSLCTXadd1chaincert, wolfSSLadd0chaincert. These API are enabled for 3rd party compatibility features: enable-opensslall, enable-opensslextra, enable-lighty, enable-stunnel, enable-nginx, enable-haproxy. This issue is not remotely exploitable, and would require that the application context loading certificates is compromised.