Versions mentioned in the description apply to the upstream
Remediation section below for
Alpine:3.10 relevant versions.
Curl_smtp_escape_eob in lib/smtp.c in curl 7.54.1 to and including curl 7.60.0 has a heap-based buffer overflow that might be exploitable by an attacker who can control the data that curl transmits over SMTP with certain settings (i.e., use of a nonstandard --limit-rate argument or CURLOPT_BUFFERSIZE value).
curl to version 7.61.0-r0 or higher.