wikiplugin_includetpl in lib/wiki-plugins/wikiplugin_includetpl.php in Tiki before 28.3 mishandles input to an eval. The fixed versions are 21.12, 24.8, 27.2, and 28.3.
https://gitlab.com/tikiwiki/tiki/-/commit/f3f36c1ac702479209acfcaec5789d2fd1f996bc
https://gitlab.com/tikiwiki/tiki/-/commit/be8dc1aa220fbceb07a7a5dc36416243afccd358
https://gitlab.com/tikiwiki/tiki/-/commit/9ffb4ab21bd86837370666ecd6afd868f3d7877a
https://gitlab.com/tikiwiki/tiki/-/commit/801ed912390c2aa6caf12b7b953e200f5d4bc0b1
https://gitlab.com/tikiwiki/tiki/-/commit/406bea4f6c379a23903ecfd55e538d90fd669ab0