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 <foreignObject> tag.
Details
The vulnerability is located in nicegui/elements/interactive_image.js.
The component uses the following code to render content:
<g v-html="content"></g>
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
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](https://picsum.photos/640/360)')
# Payload: Embeds raw HTML execution inside SVG
# This executes immediately when the image component is rendered
img.content = (
'<foreignObject>'
'<body xmlns="[http://www.w3.org/1999/xhtml](http://www.w3.org/1999/xhtml)">'
'<img src=x onerror=alert("XSS-SVG")>'
'</body>'
'</foreignObject>'
)
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.
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
CVE-2025-66470 has a CVSS score of 6.1 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.4.0); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2025-66470? CVE-2025-66470 is a medium-severity cross-site scripting (XSS) vulnerability in nicegui (pip), affecting versions <= 3.3.1. It is fixed in 3.4.0. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- How severe is CVE-2025-66470? CVE-2025-66470 has a CVSS score of 6.1 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of nicegui are affected by CVE-2025-66470? nicegui (pip) versions <= 3.3.1 is affected.
- Is there a fix for CVE-2025-66470? Yes. CVE-2025-66470 is fixed in 3.4.0. Upgrade to this version or later.
- Is CVE-2025-66470 exploitable, and should I be worried? Whether CVE-2025-66470 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-66470 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2025-66470? Upgrade
niceguito 3.4.0 or later.