GHSA-2m4f-cg75-76w2 NiceGUI Stored/Reflected XSS in ui.interactive_image via unsanitized SVG content

• PyPI nicegui: < 3.4.0 → fixed in 3.4.0

Summary A Cross-Site Scripting (XSS) vulnerability exists in the `ui.interactive_image` component of NiceGUI (v3.3.1 and earlier). The component renders SVG content using Vue's `v-html` directive without any sanitization. This allows attackers to inject malicious HTML or JavaScript via the SVG `` tag. Details The vulnerability is located in `nicegui/elements/interactive_image.js`. The component uses the following code to render content: ```javascript ``` Vue's v-html directive renders raw HTML strings into the DOM. If an application allows user-controlled input to be passed to the content property of an interactive image, an attacker can embed a tag containing malicious scripts, bypassing typical image restrictions. PoC ```python from nicegui import ui @ui.page('/') def main(): ui.label('NiceGUI SVG XSS PoC') # Standard image loading img = ui.interactive_image('https://picsum.photos/640/360') # Payload: Embeds raw HTML execution inside SVG # This executes immediately when the image component is rendered img.content = ( '' '' '' '' '' ) ui.run() ``` Impact • Type: Reflected / Stored XSS (depending on data source) • Severity: Moderate • Impact: Attackers can inject malicious scripts that execute whenever the image component is rendered or updated. This is particularly dangerous for dashboards or multi-user applications displaying user-generated content or annotations.