curl supports the -t command line option, known as CURLOPT_TELNETOPTIONS in libcurl. This rarely used option is used to send variable=content pairs to TELNET servers. https://curl.se/docs/CVE-2021-22898.html CREATE(Triage):(User=admin) CVE-2021-22898 (https://nvd.nist.gov/vuln/detail/CVE-2021-22898)