TELNET stack contents disclosure again

Open Source Vulnerabilities CVE-2021-22925

curl supports the `-t` command line option, known as `CURLOPT_TELNETOPTIONS`in libcurl. This rarely used option is used to send variable=content pairs toTELNET servers.Due to flaw in the option parser for sending `NEW_ENV` variables, libcurlcould be made to pass on uninitialized data from a stack based buffer to theserver. Therefore potentially revealing sensitive internal information to theserver using a clear-text network protocol.This could happen because curl did not call and use sscanf() correctly whenparsing the string provided by the application.

Open Source Vulnerabilities CURL-CVE-2021-22925

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. Due to 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. Therefore potentially revealing sensitive internal information to the server using a clear-text network protocol. This could happen because curl did not call and use `sscanf()` correctly when parsing the string provided by the application. The previous curl security vulnerability [CVE-2021-22898](https://curl.se/docs/CVE-2021-22898.html) is almost identical to this one but the fix was insufficient so this security vulnerability remained.