Principal Security Engineer - Fuzzing Specialist

Camwebdir; United Kingdom; Hybrid; GBP 90,000 - 140,000; Full time

Job summary

Arm is seeking a Principal Security Engineer specialising in fuzzing to own and evolve a coverage-guided fuzzing program. You will craft high-performance fuzzing harnesses, expand seed corpora, and build custom sanitizers to push code coverage and resilience. Strong debugging, scripting, and collaboration with product teams are essential.

Hybrid working model; you will drive CVE-level findings to remediation and contribute to security postures across services and protocols.

Qualifications

• Experience in coverage-guided fuzzing for security testing.
• Strong programming in C/C++ with Python for automation.
• Ability to triage crashes and reproduce issues.
• Familiarity with fuzzing infrastructure at scale.

Responsibilities

• Map and prioritise fuzzing surfaces across services and protocols; maintain a living risk-based roadmap.
• Design, build, and extend fuzzing harnesses with libFuzzer, AFL++, or Honggfuzz.
• Grow seed corpus and apply targeted mutation strategies to improve coverage.
• Automate crash triage and root-cause analysis; distinguish exploitable bugs from faults.
• Develop custom sanitizers to expose missed bug classes.
• Validate fixes and guard against regressions via differential fuzzing.
• Assess disclosures to refine fuzzing detectability and harness coverage.
• Document findings and share insights with engineering teams.

Skills

Coverage-guided fuzzing

Fuzzing frameworks

C/C++ programming

Python scripting

Memory-safety concepts

Debugging tools

Tools

libFuzzer

AFL++

Honggfuzz

Job description

Principal Security Engineer - Fuzzing Specialist

Job Overview

As a Security Engineer – Fuzzing Specialist, you will own and evolve our coverage-guided fuzzing program. Your mission is to uncover hard-to-reach security flaws before attackers do, drive fixes to closure, and help product teams to embrace dynamic testing like fuzzing. You’ll scout for new attack surfaces, craft high-performance fuzzing harnesses, and design custom sanitisers that push the state of the art. Success means measurable coverage gains, actionable crash reports, and products that ship with provable resilience.

Responsibilities

• Map & prioritise fuzzing surfaces across services, libraries, APIs, and protocols; maintain a living risk-based roadmap.
• Design, build, and extend fuzzing harnesses (libFuzzer, AFL++, Honggfuzz, etc.) that improve code-path exploration and minimise false positives.
• Continuously improve coverage by growing seed corpus, deploying targeted mutation strategies, and integrating new instrumentation techniques.
• Automate crash triage & root-cause analysis; distinguish exploitable vulnerabilities from benign faults and drive CVE-level findings to remediation.
• Develop custom sanitisers to expose classes of bugs traditional fuzzing misses.
• Validate fixes & guard against regressions through differential fuzzing and regression corpora.
• Assess external disclosures (bug bounties, supply‑chain advisories) to determine fuzzing detectability and refine harnesses when gaps are found.
• Document, report, and share insights — from coverage metrics to post‑mortems to create data‑driven security.

Required Skills and Experience

• 1+ years in application or product security with a deep focus on coverage‑guided fuzzing.
• Hands‑on expertise with at least one modern fuzzing framework (e.g., libFuzzer, AFL++, Honggfuzz).
• Proficient in C/C++ plus strong scripting ability in Python for automation.
• Solid understanding of memory‑safety vulnerabilities, undefined behaviour, sanitisers, and compiler instrumentation.
• Demonstrated ability to triage crashes using debuggers, profilers, and reverse‑engineering tools (gdb/lldb, IDA/Ghidra).
• Excellent written communication for documenting findings and influencing engineering teams.

Nice To Have Skills and Experience

• Contributions to open‑source fuzzing tools, sanitisers, or security research publications.
• Knowledge of distributed fuzzing at scale (GCP/AWS, Kubernetes, or bare‑metal clusters).
• Familiarity with kernel, embedded, or firmware fuzzing (e.g., Syzkaller, QEMU‑based harnesses).
• Background in reverse engineering, static analysis or symbolic execution.
• Experience integrating fuzzing into CI/CD pipelines and tracking coverage metrics.

#LI-CI1

Accommodations at Arm

At Arm, we want to build extraordinary teams. If you need an adjustment or an accommodation during the recruitment process, please email [email protected]. To note, by sending us the requested information, you consent to its use by Arm to arrange for appropriate accommodations. All accommodation or adjustment requests will be treated with confidentiality, and information concerning these requests will only be disclosed as necessary to provide the accommodation. Although this is not an exhaustive list, examples of support include breaks between interviews, having documents read aloud, or office accessibility. Please email us about anything we can do to accommodate you during the recruitment process.

Hybrid Working at Arm

Arm’s approach to hybrid working is designed to create a working environment that supports both high performance and personal wellbeing. We believe in bringing people together face to face to enable us to work at pace, whilst recognizing the value of flexibility. Within that framework, we empower groups/teams to determine their own hybrid working patterns, depending on the work and the team’s needs. Details of what this means for each role will be shared upon application. In some cases, the flexibility we can offer is limited by local legal, regulatory, tax, or other considerations, and where this is the case, we will collaborate with you to find the best solution. Please talk to us to find out more about what this could look like for you.

Equal Opportunities at Arm

Arm is an equal opportunity employer, committed to providing an environment of mutual respect where equal opportunities are available to all applicants and colleagues. We are a diverse organization of dedicated and innovative individuals, and don’t discriminate on the basis of race, color, religion, sex, sexual orientation, gender identity, national origin, disability, or status as a protected veteran.