Gridea version 0.9.3 allows an external attacker to execute arbitrary code remotely on any client attempting to view a malicious markdown file through Gridea. This is possible because the application has the 'nodeIntegration' option enabled.

Gridea v0.8.0 has an XSS vulnerability through which the Nodejs module can be called to achieve arbitrary code execution, as demonstrated by child_process.exec and the "<img src=# onerror='eval(new Buffer(" substring.