Cursor Agent is vulnerable prompt injection via Editor Special Files

Cursor is a code editor built for programming with AI. Cursor allows writing in-workspace files with no user approval in versions less than 1.3.9. If the file is a dotfile, editing it requires approval but creating a new one doesn't. Hence, if sensitive editor files, such as the .vscode/settings.json file don't already exist in the workspace, an attacker can chain a indirect prompt injection vulnerability to hijack the context to write to the settings file and trigger RCE on the victim without user approval. This is fixed in version 1.3.9.