CVE-2025-66470 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in nicegui. A fix is available for nicegui — see the affected versions and patch details below.
NiceGUI Stored/Reflected XSS in ui.interactive_image via unsanitized SVG content
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-66470.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-66470 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
niceguiReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
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 <foreignObject> 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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | nicegui | all versions | 3.4.0pip install --upgrade 'nicegui==3.4.0' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nicegui, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update nicegui to 3.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-66470 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-66470 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-66470. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-66470 in your dependencies?
O3 Security finds CVE-2025-66470 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.