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Cloudflare

Security Engineer Intern (Summer 2026)

Cloudflare
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onsite entry internship In-Office

First indexed 26 Apr 2026

Description

About Us

At Cloudflare, we are on a mission to help build a better Internet. Today the company runs one of the world’s largest networks that powers millions of websites and other Internet properties for customers ranging from individual bloggers to SMBs to Fortune 500 companies.

As a Security Engineer Intern, you will work alongside experienced security engineers to identify vulnerabilities, harden our infrastructure, and build tools that protect billions of Internet users. We are looking for interns who are curious, proactive, and able to approach problems with a “security-first” mindset.

Responsibilities

  • Ship and deliver security-focused projects over 12-16 weeks with autonomy and support.
  • Work cross-functionally with Product, Infrastructure, and Engineering teams to integrate security into every stage of the development lifecycle.
  • Work closely with a mentor to guide you through the internship, develop your security expertise, and help with career goals.
  • Build your network across the company through our various in and out of office socials, networking programs, Employee Resource Group (ERG) programs, and Activity Groups.
  • Present your security project to the entire company at the end of the internship.
  • Connect and learn from our executives and leadership team including our co-founders.
  • Write for our Cloudflare blog (e.g., documenting a new security tool or a vulnerability research finding) and be featured on Cloudflare.tv sessions.

About the Internship Program

The ideal Security Engineering intern is passionate about making the Internet a more secure place. You will work alongside experienced security engineers to identify vulnerabilities, harden our infrastructure, and build tools that protect billions of Internet users.

What would you do as a Cloudflare intern?

  • Ship and deliver security-focused projects over 12-16 weeks with autonomy and support.
  • Work cross-functionally with Product, Infrastructure, and Engineering teams to integrate security into every stage of the development lifecycle.
  • Work closely with a mentor to guide you through the internship, develop your security expertise, and help with career goals.
  • Build your network across the company through our various in and out of office socials, networking programs, Employee Resource Group (ERG) programs, and Activity Groups.
  • Present your security project to the entire company at the end of the internship.
  • Connect and learn from our executives and leadership team including our co-founders.
  • Write for our Cloudflare blog (e.g., documenting a new security tool or a vulnerability research finding) and be featured on Cloudflare.tv sessions.

Examples of desirable skills, knowledge and experience

  • Education: Currently pursuing a degree in Computer Science, Cybersecurity, Computer Engineering, or a related technical field.
  • Security Fundamentals: A solid understanding of the OWASP Top 10, common attack vectors (XSS, SQLi, CSRF), and how to mitigate them.
  • Demonstrated critical thinking skills and drive to learn and adapt new technologies.
  • Curiosity, empathy and ability to get things done.
  • Ability to commit to a minimum 12 week summer internship.
  • In office 3-5 days a week in the location of the internship.
  • Local to Lisbon; relocation not provided.
  • Bonus: Demonstrated passion for security & software development, such as personal projects, open-source contributions, or experience with our developer platform using Cloudflare for Students.
This listing is enriched and indexed by YubHub. To apply, use the employer's original posting: https://job-boards.greenhouse.io/cloudflare/jobs/7582157