curl 7.7 through 7.76.1 suffers from an information disclosure when the `-t` command line option, known as `CURLOPT_TELNETOPTIONS` in libcurl, is used to send variable=content pairs to TELNET servers. Due to a flaw in the option parser for sending NEW_ENV variables, libcurl could be made to pass on uninitialized data from a stack based buffer to the server, resulting in potentially revealing sensitive internal information to the server using a clear-text network protocol.
https://www.oracle.com/security-alerts/cpujan2022.html
https://www.oracle.com/security-alerts/cpuapr2022.html
https://www.oracle.com//security-alerts/cpujul2021.html
https://www.debian.org/security/2022/dsa-5197
https://lists.debian.org/debian-lts-announce/2022/08/msg00017.html
https://lists.debian.org/debian-lts-announce/2021/08/msg00017.html
https://hackerone.com/reports/1176461
https://github.com/curl/curl/commit/39ce47f219b09c380b81f89fe54ac586c8db6bde
https://curl.se/docs/CVE-2021-22898.html
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf