Security Engineer Intern (summer 2026)

Cloudflare Cloudflare · Enterprise · Lisbon, Portugal · University

Cloudflare is seeking a Security Engineer Intern for Summer 2026 in Lisbon, Portugal. The intern will work on security-focused projects, collaborate with cross-functional teams, and learn to defend systems at scale. The role requires a strong understanding of security fundamentals and a proactive, security-first mindset. Bonus points for demonstrated passion for security and software development.

What you'd actually do

  1. Ship and deliver security-focused projects over 12-16 weeks with autonomy and support.
  2. Work cross-functionally with Product, Infrastructure, and Engineering teams to integrate security into every stage of the development lifecycle.
  3. Work closely with a mentor to guide you through the internship, develop your security expertise, and help with career goals.
  4. 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.
  5. Present your security project to the entire company at the end of the internship.

Skills

Required

  • Currently pursuing a degree in Computer Science, Cybersecurity, Computer Engineering, or a related technical field.
  • 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.

Nice to have

  • Demonstrated passion for security & software development, such as personal projects, open-source contributions, or experience with our developer platform using Cloudflare for Students.

What the JD emphasized

  • security-first mindset