The vulnerability occurs when processing the oldFileName parameter in writeFileContent requests. TemplateAction.writeFileContent handles the vulnerable endpoint and passes user input to FileUtil.deleteFile. BasicUtil.getRealTemplatePath is involved in path resolution but fails to sanitize traversal sequences. These functions form the attack chain: user input flows through TemplateAction -> BasicUtil (path resolution) -> FileUtil (deletion). High confidence in TemplateAction and FileUtil roles based on explicit references in GHSA description and issue #59. Medium confidence in BasicUtil's role as path resolver mentioned in issue comments but without seeing actual path sanitization flaws in code.