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Vulnerability record · CVE-2026-27156 · published 24 February 2026

CVE-2026-27156: Zauberzeug nicegui cross-site scripting vulnerability

Zauberzeug · Nicegui

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.

6.1 CVSS 3.1 Medium EPSS 0.27% · top 82.3% CWE-79 · Cross-site scripting
6.1CVSS 3.1 base score
0.27%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

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

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Source: NIST National Vulnerability Database (record CVE-2026-27156), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.