Lovable
security
XSS Vulnerability in Lovable App User Input
Your Lovable app displays user-submitted content (comments, profile names, form inputs) without properly sanitizing it. This allows attackers to inject malicious JavaScript that runs in other users' browsers.
Cross-site scripting (XSS) is a serious vulnerability that can steal user sessions, redirect users to phishing sites, or modify what your app displays. If your app has any feature where one user's input is shown to another user, it may be vulnerable.
The issue often goes unnoticed until someone submits a script tag in a form field and it executes, or until your app is flagged in a security scan.
Error Messages You Might See
Content Security Policy violation
Refused to execute inline script
Unsafe HTML content detected
Common Causes
- Using dangerouslySetInnerHTML — Lovable may generate React code that renders user content as raw HTML
- No input sanitization — User input is stored and displayed exactly as entered, including HTML and script tags
- Template literals in DOM — User data inserted into the page using template strings without escaping
- Missing Content-Security-Policy headers — No CSP headers to prevent inline script execution
How to Fix It
- Never use dangerouslySetInnerHTML with user data — Replace it with regular text rendering that auto-escapes HTML
- Install DOMPurify — If you must render HTML, use a sanitization library like DOMPurify to strip malicious content
- Add Content-Security-Policy headers — Configure CSP headers to prevent inline script execution
- Validate and sanitize on the server — Clean user input before storing it in the database, not just when displaying it
- Test with common XSS payloads — Try submitting <script>alert('xss')</script> in your form fields to verify they're safe
Real developers can help you.
MFox
Full-stack professional senior engineer (15+years). Extensive experience in software development, qa, and IP networking.
Jaime Orts-Caroff
I'm a Senior Android developer, open to work in various fields
Luca Liberati
I work on monoliths and microservices, backends and frontends, manage K8s clusters and love to design apps architecture
Milan Surelia
Milan Surelia is a Mobile App Developer with 5+ years of experience crafting scalable, cross-platform apps at 7Span and Meticha. At 7Span, he engineers feature-rich Flutter apps with smooth performance and modern UI. As the Co-Founder of Meticha, he builds open-source tools and developer-focused products that solve real-world problems.
Expertise:
💡 Developing cross-platform apps using Flutter, Dart, and Jetpack Compose for Android, iOS, and Web.
🖋️ Sharing insights through technical writing, blogging, and open-source contributions.
🤝 Collaborating closely with designers, PMs, and developers to build seamless mobile experiences.
Notable Achievements:
🎯 Revamped the Vepaar app into Vepaar Store & CRM with a 2x performance boost and smoother UX.
🚀 Launched Compose101 — a Jetpack Compose starter kit to speed up Android development.
🌟 Open source contributions on Github & StackOverflow for Flutter & Dart
🎖️ Worked on improving app performance and user experience with smart solutions.
Milan is always happy to connect, work on new ideas, and explore the latest in technology.
Basel Issmail
’m a Senior Full-Stack Developer and Tech Lead with experience designing and building scalable web platforms. I work across the full development lifecycle, from translating business requirements into technical architecture to delivering reliable production systems.
My work focuses on modern web technologies, including TypeScript, Angular, Node.js, and cloud-based architectures. I enjoy solving complex technical problems and helping teams turn product ideas and prototypes into working platforms that can grow and scale.
In addition to development, I often collaborate closely with product managers, business analysts, designers, and QA teams to ensure that solutions align with both technical and business goals.
I enjoy working with startups and product teams where I can contribute both as a hands-on engineer and as a technical partner in designing and delivering impactful software.
Kingsley Omage
Fullstack software engineer passionate about AI Agents, blockchain, LLMs.
Richard McSorley
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Matthew Butler
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Omar Faruk
As a Product Engineer at Klasio, I contributed to end-to-end product development, focusing on scalability, performance, and user experience.
My work spanned building and refining core features, developing dynamic website templates, integrating secure and reliable payment gateways, and optimizing the overall system architecture.
I played a key role in creating a scalable and maintainable platform to support educators and learners globally.
I'm enthusiastic about embracing new challenges and making meaningful contributions.
Prakash Prajapati
I’m a Senior Python Developer specializing in building secure, scalable, and highly available systems. I work primarily with Python, Django, FastAPI, Docker, PostgreSQL, and modern AI tooling such as PydanticAI, focusing on clean architecture, strong design principles, and reliable DevOps practices. I enjoy solving complex engineering problems and designing systems that are maintainable, resilient, and built to scale.
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Get HelpFrequently Asked Questions
What is XSS and why is it dangerous?
Cross-site scripting (XSS) allows attackers to inject malicious scripts into your app. When other users visit the page, the script runs in their browser and can steal their login sessions, personal data, or redirect them to fake sites.
Can React prevent XSS automatically?
React escapes content by default when you use JSX expressions like {userInput}. However, using dangerouslySetInnerHTML or inserting content via DOM manipulation bypasses this protection.