What’s Vulnerable › Vulnerabilities

CVE-2026-27156: NiceGUI has XSS via Code Injection

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-02-24 · updated 2026-06-17
• Weakness: CWE-79

Description

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 products

• zauberzeug nicegui: before 3.8.0 — fixed in 3.8.0

How to fix

Upgrade to a fixed version: zauberzeug nicegui 3.8.0. Check the vendor advisory for mitigations.

References

• https://github.com/zauberzeug/nicegui/commit/1861f59cc374ca0dc9d970b157ef3774720f8dbf
• https://github.com/zauberzeug/nicegui/security/advisories/GHSA-78qv-3mpx-9cqq

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