Trento, IT → Saarbrücken, DE

Matteo Leonelli

PhD Candidate/CISPA Helmholtz Center for Information Security /advisor: Prof. Dr. Thorsten Holz

Security researcher working on fuzzing, automated testing, and vulnerability discovery — building tools that find the inputs a program's authors never imagined, and the bugs that follow.

Biography

Matteo Leonelli is a Ph.D. fellow at the CISPA Helmholtz Center for Information Security, supervised by Prof. Dr. Thorsten Holz. Prior to this, he earned an M.Eng. in Security from Saarland University (2024) and a B.Sc. in Computer Science from the University of Trento (2021). His research focuses on fuzzing, automated testing, and vulnerability discovery, with a particular emphasis on novel approaches for detecting unusual behaviors and bug classes.

Publications

2026

THEMIS: Context-Aware Grey-box Fuzzing for WordPress Plugins

Matteo Leonelli, David Jannis Dewes, Thorsten Holz

IEEE European Symposium on Security and Privacy (EuroS&P)

[pdf] [code]

2025

SBFT Tool Competition 2025 – Fuzzing Track

Addison Crump, Sahil Sihag, Matteo Leonelli

Workshop on Search-Based and Fuzz Testing (SBFT)

[pdf]

TwinFuzz: Differential Testing of Video Hardware Acceleration Stacks

Matteo Leonelli, Addison Crump, Meng Wang, Florian Bauckholt, Keno Hassler, Ali Abbasi, Thorsten Holz

Network and Distributed System Security Symposium (NDSS)

[pdf] [code]

2021

Secure Pull Printing with QR Codes and National eID Cards: A Software-oriented Design and an Open-source Implementation

Matteo Leonelli, Umberto Morelli, Giada Sciarretta, Silvio Ranise

ACM Conference on Data and Application Security and Privacy (CODASPY)

[pdf] [code]

2020

Pull Printing with National eID Cards: An Open-source and Software-oriented Implementation

Matteo Leonelli, Umberto Morelli, Silvio Ranise, Giada Sciarretta

Italian Conference on Cybersecurity (ITASEC)

Experience

  1. Mar 2024 — Present

    Ph.D. Candidate

    CISPA Helmholtz Center for Information Security, Saarland University

    Research on functional and security-focused automated fuzz testing for complex system security, with work published at EuroS&P and NDSS and multiple CVEs discovered in widely-deployed software.

  2. Sep 2025 — Nov 2025

    Applied Scientist Intern

    Amazon Web Services (AWS), Paris

    Designed and implemented automated fuzz testing pipelines to evaluate and ensure data integrity in Amazon S3, applying grey-box fuzzing techniques to large-scale distributed cloud storage infrastructure.

  3. Apr 2022 — Mar 2024

    Research Assistant

    CISPA Helmholtz Center for Information Security, Saarland University

    Collaborated with Ph.D. researchers on automated root cause analysis of fuzzer-discovered bugs and on LLM-driven automatic fuzzing harness generation.

  4. Mar 2023 — Jan 2024

    Master's Thesis

    CISPA Helmholtz Center for Information Security, Saarland University

    Research on software and hardware fuzzing in collaboration with Intel.

  5. May 2021 — Sep 2021

    Bachelor Thesis

    Fondazione Bruno Kessler, Trento

    Research resulting in the CODASPY'21 paper on secure pull printing with QR codes and national eID cards.

  6. May 2021 — Aug 2021

    IoT Security Risk Assessment — CySec Project

    Bitahoy, Saarbrücken

    Assessed IoT device security using Wireshark to capture and analyze network traffic for malicious payloads, and built infrastructure to automatically cluster and flag suspicious activity in network logs.

  7. Feb 2019 — Dec 2020

    Junior Researcher

    Fondazione Bruno Kessler, Trento

    Designed authentication protocols using the Italian CIE 3.0 smart card standard.

  8. Dec 2017 — Dec 2020

    Full Stack Developer

    Matrix Tech, Trento

    Developed a full-stack web service for access control and real-time occupancy monitoring, integrated with proprietary embedded hardware.

  9. 2018 — 2019

    Developer

    OGP

    Developed customer-facing websites and integrated new features.

  10. Nov 2018 — Jan 2019

    Software Developer Intern

    Fondazione Bruno Kessler, Security & Trust Lab, Trento

    Mobile developer internship focused on secure application development.

  11. Jun 2017 — Jul 2017

    Java Developer Intern

    Fondazione Bruno Kessler, Smart Community Lab, Trento

    Java developer involved in data analysis and software development.

Education

  1. 2024 — present

    Ph.D. in Cybersecurity

    CISPA Helmholtz Center for Information Security, Germany

  2. 2021 — 2024

    M.Eng. in Cybersecurity

    Saarland University, Germany

  3. 2018 — 2021

    B.Sc. in Computer Science

    University of Trento, Italy

  4. 2014 — 2018

    High School Diploma in Computer Science

    Marconi Rovereto, Italy

Achievements & CVEs

Reported
Modern Events Calendar — arbitrary option update & local file inclusion 2025 · 100,000+ installs · found with THEMIS
Reported
rtMedia for WordPress — local file inclusion 2025 · 10,000+ installs · found with THEMIS
Confirmed
Firefox — cross-tab information leak via hardware-accelerated video decoding 2024 · Confirmed by Mozilla · found with TwinFuzz

Miscellaneous

  1. 2026

    Attended IEEE S&P

    San Francisco

  2. 2025

    Organized SBFT Workshop

    ICSE 2025

  3. 2019

    Organized ProM Camp

    Trento

  4. 2018

    Attended ProM Camp

    Trento

Teaching

  1. 2025 — 2026

    Research Assistant Mentor

    CISPA Helmholtz Center for Information Security

  2. 2025

    Bachelor's Thesis Supervisor

    CISPA Helmholtz Center for Information Security

  3. 2024

    Teaching Assistant — System Security

    CISPA Helmholtz Center for Information Security

  4. 2023

    Teaching Assistant — Security

    University of Saarland

  5. 2023

    Teaching Assistant — Human Computer Interaction

    University of Saarland

  6. 2021

    Teaching Assistant — Programming 1

    University of Trento