Storybook is a frontend workshop for building user interface components and pages in isolation. From 8.0.0 until 8.6.19, 9.1.21, 10.6.2, and 11.0.0-alpha.6, a malicious website can interact with the preview of a running Storybook development server. Insufficient iframe embedding and message-origin restrictions can allow attacker-controlled events to reach the running preview. A developer must visit the malicious website and interact with the injected interface. The attack can cause unauthorized changes to story files and, if a changed file is later executed by a local runtime, arbitrary code execution with the developer's privileges. This issue is fixed in 8.6.19, 9.1.21, 10.6.2, and 11.0.0-alpha.6.