🛡️ Sentinel: [HIGH] Fix XSS vulnerability in DescriptionPreview

[bobdivx]

🚨 Severity: HIGH
💡 Vulnerability: Cross-Site Scripting (XSS) vulnerability was found in src/components/upload/DescriptionPreview.tsx. The component used dangerouslySetInnerHTML to render HTML provided directly from an API endpoint, removing only {} sequences, meaning malicious <script> tags or javascript: links could bypass validation.
🎯 Impact: An attacker could craft a malicious tracker description containing XSS payloads which would execute code in the context of the frontend app when viewed by the user.
🔧 Fix: Installed and imported isomorphic-dompurify, which is applied to sanitize the input strings before they are injected into dangerouslySetInnerHTML.
✅ Verification: Verified that XSS vectors like <img src="javascript:alert(1)"> are successfully stripped without breaking formatting. Build and test suite pass successfully. Added a note to .jules/sentinel.md.

---

PR created automatically by Jules for task 6447510616318228540 started by @bobdivx

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
popcorn-client	Ready	Preview, Comment	Mar 26, 2026 7:18am

[google-labs-jules]

👋 Jules, reporting for duty! I'm here to lend a hand with this pull request.

When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down.

I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job!

For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with @jules. You can find this option in the Pull Request section of your global Jules UI settings. You can always switch back!

New to Jules? Learn more at jules.google/docs.

---

For security, I will only act on instructions from the user who triggered this task.

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request delivers a critical security enhancement by resolving a high-severity Cross-Site Scripting (XSS) vulnerability within the DescriptionPreview component. The change introduces robust HTML sanitization using isomorphic-dompurify, ensuring that any dynamic HTML content, whether from user input or API responses, is safely rendered. This significantly improves the application's resilience against injection attacks and protects users from malicious content.

Highlights

• XSS Vulnerability Fix: Addressed a high-severity Cross-Site Scripting (XSS) vulnerability in the DescriptionPreview component.
• HTML Sanitization Implemented: Integrated isomorphic-dompurify to sanitize HTML content, preventing malicious script injection.
• Security Documentation Added: Created a new Sentinel markdown file to document the vulnerability, lessons learned, and prevention measures.

🧠 New Feature in Public Preview: You can now enable Memory to help Gemini Code Assist learn from your team's feedback. This makes future code reviews more consistent and personalized to your project's style. Click here to enable Memory in your admin console.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for GitHub and other Google products, sign up here.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This pull request addresses a Cross-Site Scripting (XSS) vulnerability in the DescriptionPreview component by integrating isomorphic-dompurify to sanitize HTML content. The sanitizePreviewHtml function now uses DOMPurify.sanitize() after removing residual placeholder sequences. The package.json and package-lock.json files have been updated to include the new dependency and reflect other dependency changes. A new markdown file, .jules/sentinel.md, documents the vulnerability, lessons learned, and prevention strategies. A review comment suggests explicitly configuring DOMPurify options for improved security and clarity.

[gemini-code-assist]

While DOMPurify.sanitize() provides robust protection against XSS by default, it's good practice to explicitly configure its options (e.g., ALLOWED_TAGS, ALLOWED_ATTR) to precisely match the expected and allowed HTML content. This provides an additional layer of defense and makes the security policy explicit, preventing unintended allowances if DOMPurify's defaults change or if specific application requirements are stricter.