Founding CTO (+ Equity) at VC-backed AI security startup

Added 24/08/2026

An innovative, VC-backed startup at the forefront of AI security is seeking a visionary Founding CTO to join as a core member of the leadership team. This is a unique opportunity to take charge of the technology strategy and execution within a fast-paced, high-growth environment. As the Founding CTO, you will work closely with the founding team to define the technical roadmap, architect scalable solutions, and build a world-class engineering team. You will have significant influence over product direction and play a pivotal role in shaping the company’s culture and long-term success. Key responsibilities include designing and implementing secure, scalable...

Senior Software Security Engineer (£98k-£115k + Equity) at Harmonic Security Inc.

Added 03/09/2026

We are looking for a Senior Software Security Engineer to help build secure, resilient products in a fast-moving technology environment. This is a hands-on role for an experienced engineer who can combine strong software development skills with a deep understanding of application and cloud security. You will work closely with engineering, product and infrastructure teams to embed security throughout the software development lifecycle, from design and implementation through to deployment and ongoing improvement. The position offers a salary of £98,000–£115,000 plus equity. Your responsibilities will include designing and implementing secure, scalable services; reviewing code and architecture for vulnerabilities; developing security...

Senior IT Support & Endpoint Security Engineer at Cloudnc

Added 03/09/2026

We are seeking a Senior IT Support & Endpoint Security Engineer to provide expert technical support and help maintain a secure, reliable, and efficient workplace technology environment. This role will combine hands-on troubleshooting with endpoint administration, security operations, and continuous improvement. You will act as an escalation point for complex technical issues, supporting users across a range of devices, operating systems, applications, and cloud-based services. Key responsibilities will include managing and securing laptops, desktops, mobile devices, and other endpoints throughout their lifecycle; administering endpoint management, identity, access, and security platforms; and monitoring device compliance, vulnerabilities, and security alerts. You will...

Founding Security Researcher

Added 11/09/2026

We are seeking a Founding Security Researcher to establish and lead the security research function from the ground up. This is a highly influential role for an experienced security professional who enjoys investigating emerging threats, translating technical findings into practical defensive strategies, and shaping the direction of a growing security programme. You will work closely with engineering, product, infrastructure, and leadership teams to identify risks, strengthen security controls, and build a culture of security by design. Your responsibilities will include conducting in-depth research into vulnerabilities, attack techniques, malware, exploitation methods, and relevant developments across the threat landscape. You will design...

Senior Offensive Security Engineer — Founding Security Hire

Added 01/09/2026

We are seeking a Senior Offensive Security Engineer to become the founding security hire and establish the foundations of a high-impact security function. This is a hands-on role for an experienced security professional who enjoys working across product, infrastructure, cloud environments, and organisational processes. You will define and execute a practical offensive security programme, identify meaningful risks, and partner closely with engineering and leadership teams to improve the security of systems, applications, and customer-facing services. Your responsibilities will include planning and conducting penetration tests, red-team exercises, vulnerability assessments, and threat-led reviews across web applications, APIs, cloud platforms, networks, and internal...

AI Security Researcher/Research Engineer

Added 08/09/2026

We are seeking an AI Security Researcher/Research Engineer to investigate emerging threats, vulnerabilities, and defensive techniques across artificial intelligence and machine learning systems. You will help assess the security, reliability, and resilience of models, data pipelines, agents, and supporting infrastructure, translating research findings into practical improvements. This role is suited to someone who enjoys working across theoretical research, hands-on experimentation, and engineering implementation in a fast-changing technical environment. Your responsibilities will include designing and executing evaluations of model behaviour, adversarial robustness, privacy, data poisoning, prompt injection, model extraction, misuse, and other relevant attack or failure modes. You will develop proof-of-concept...

SWE - User Land Security Researcher, SEAR (Early Career)

Added 01/09/2026

We are seeking an early-career Software Engineer and User-Land Security Researcher to help identify, analyse, and address security weaknesses in user-space software and systems. You will work with experienced security engineers and researchers to investigate vulnerabilities, develop proof-of-concept demonstrations, and improve the resilience of products and services. This role is suited to someone who enjoys understanding how software works at a low level and applying that knowledge to practical security problems. Your responsibilities will include performing vulnerability research across applications, libraries, and operating-system components; analysing source code, binaries, crash data, and system behaviour; and developing tools, scripts, and automated techniques...

Junior Cyber Security Researcher - September 2027

Added 26/08/2026

We are seeking a Junior Cyber Security Researcher to join a forward-looking security team from September 2027. This entry-level role is suited to someone with a strong interest in cyber security, threat research and emerging technologies, who is keen to develop practical experience in a collaborative environment. You will support investigations into new and evolving threats, contribute to security research projects and help translate technical findings into clear, actionable intelligence. Your responsibilities will include monitoring threat activity, researching vulnerabilities, malware, attack techniques and relevant security trends, and assisting with the assessment of potential risks. You will help gather, validate and...

Security Researcher

Added 19/08/2026

We are seeking a talented and motivated Security Researcher to join our dynamic team. In this role, you will be responsible for identifying, analyzing, and mitigating security vulnerabilities across various platforms and systems. You will conduct in-depth research on emerging threats and trends in cybersecurity, providing valuable insights to enhance our security posture. Your expertise will play a crucial role in developing effective security strategies and solutions that protect our digital assets and ensure compliance with industry standards. The ideal candidate will have a solid understanding of security protocols and technologies, along with hands-on experience in vulnerability assessment, penetration testing,...

AI Security Researcher

Added 18/08/2026

We are seeking a talented AI Security Researcher to join our dynamic team, focused on advancing the security of artificial intelligence systems. The ideal candidate will be responsible for conducting in-depth research on AI vulnerabilities, developing innovative security protocols, and implementing effective mitigation strategies. You will work collaboratively with cross-functional teams to identify potential threats and enhance the resilience of AI applications against adversarial attacks. Your contributions will play a vital role in safeguarding sensitive data and maintaining the integrity of AI technologies. Key responsibilities include analyzing current AI security landscapes, designing and executing experiments to assess the robustness of...

Cyber Security Researcher

Added 27/07/2026

We are seeking a skilled Cyber Security Researcher to join our dynamic team. In this role, you will be responsible for conducting in-depth research on emerging cyber threats, vulnerabilities, and security solutions. You will analyze security incidents, develop threat models, and contribute to the design of effective security measures. Your expertise will help to inform the development of innovative security technologies and protocols, ensuring they are robust against potential attacks. Collaborating with cross-functional teams, you will also prepare comprehensive reports and present findings to stakeholders, enhancing awareness and understanding of cyber risks within the organization. The ideal candidate will possess...

Cybersecurity Tester/Researcher

Added 17/09/2026

We are seeking a Cybersecurity Tester/Researcher to assess the security of applications, infrastructure, networks and emerging technologies. The successful candidate will plan and execute authorised security assessments, identify vulnerabilities, validate their impact and communicate practical recommendations to improve resilience. This role will involve a combination of hands-on testing, technical research and collaboration with engineering, operations and risk teams. Responsibilities include conducting penetration tests, vulnerability assessments, security reviews and targeted research across web applications, APIs, mobile platforms, cloud environments, operating systems and networks. You will develop test plans and tooling, perform reconnaissance and exploitation within approved boundaries, analyse findings, and produce...

Cybersecurity Tester/Researcher

Added 17/09/2026

We are seeking a Cybersecurity Tester/Researcher to assess the security of applications, infrastructure, networks, and emerging technologies. The successful candidate will plan and conduct penetration tests, vulnerability assessments, security reviews, and controlled attack simulations across web, mobile, cloud, API, and enterprise environments. You will identify weaknesses, validate their impact, and provide clear, evidence-based recommendations that help strengthen security controls and reduce operational risk. Responsibilities include defining test scope and methodologies, performing manual and automated security testing, researching new vulnerabilities and attack techniques, developing proof-of-concept exploits where appropriate, and analysing security events or suspected compromises. You will document findings in detailed...

Vulnerability Researcher

Added 17/09/2026

We are seeking a Vulnerability Researcher to identify, analyse, and responsibly disclose security weaknesses across software, hardware, embedded systems, and networked environments. You will conduct independent and collaborative research into emerging attack techniques, develop proof-of-concept exploits, and assess the practical impact of vulnerabilities. The role will involve reverse engineering binaries, analysing source code, debugging applications, fuzzing interfaces and protocols, and investigating vulnerabilities in complex technical systems. You will be responsible for creating reliable, reproducible demonstrations of security issues and documenting your findings for both technical and non-technical audiences. Working with engineering, security, and product teams, you will help validate remediation...