CVE-2026-27156

The record

NiceGUI is a Python-based UI framework. Prior to version 3.8.0, several NiceGUI APIs that execute methods on client-side elements (`Element.run_method()`, `AgGrid.run_grid_method()`, `EChart.run_chart_method()`, and others) use an `eval()` fallback in the JavaScript-side `runMethod()` function. When user-controlled input is passed as the method name, an attacker can inject arbitrary JavaScript that executes in the victim's browser. Additionally, `Element.run_method()` and `Element.get_computed_prop()` used string interpolation instead of `json.dumps()` for the method/property name, allowing quote injection to break out of the intended string context. Version 3.8.0 contains a fix.

Affected packages

Related vulnerabilities

• GHSA-78qv-3mpx-9cqq NiceGUI vulnerable to XSS via Code Injection during client-side element function execution Same vulnerability
• CVE-2026-25732 NiceGUI is a Python-based UI framework. Also affects nicegui
• CVE-2026-25516 NiceGUI is a Python-based UI framework. Also affects nicegui
• GHSA-9ffm-fxg3-xrhh NiceGUI's Path Traversal via Unsanitized FileUpload.name Enables Arbitrary File Write Also affects nicegui
• GHSA-v82v-c5x8-w282 NiceGUI's XSS vulnerability in ui.markdown() allows arbitrary JavaScript execution… Also affects nicegui
• GHSA-mp55-g7pj-rvm2 NiceGUI has Redis connection leak via tab storage causes service degradation Also affects nicegui
• GHSA-mhpg-c27v-6mxr NiceGUI apps which use `ui.sub_pages` vulnerable to zero-click XSS Also affects nicegui
• GHSA-m7j5-rq9j-6jj9 NiceGUI apps are vulnerable to XSS which uses `ui.sub_pages` and render arbitrary… Also affects nicegui