Staff Application & Product Security Engineer

You will be the most senior hands-on application security engineer at Cleo, owning both how security is built into our products from design through release and the security posture of the products we ship, both on-premise and SaaS, as our customers experience them. This is a Staff-level individual contributor role with real program ownership: you set the standards, build the guardrails, and work directly with engineers in the code. You report to the CISO and partner daily with Engineering, and our Cloud Security team. You are not a one-person department: security engineers and consulting partners execute under your direction. Your job is to set direction, make the hard technical calls, and build leverage through automation and partners rather than carry every task yourself. 

Essential Duties & Responsibilities

Secure development lifecycle and guardrails

• Own and mature Cleo’s SSDLC: security requirements, threat modeling, and design reviews for high-risk product changes, APIs, and integrations. 

• Run and tune SAST, SCA, secrets detection, container, and IaC scanning. 

• Build reusable secure patterns, reference implementations, and policy-as-code controls that make the secure path the default path. 

• Own developer security enablement: Security Champions meeting, deliver the engineering security training campaigns, grow a named champion in every squad, and give developers practical remediation guidance, office hours, and self-service security capabilities. 

Product vulnerability management 

• Run risk-based triage, remediation, and verification for application and product vulnerabilities, including remediation SLAs, escalation, and exceptions. Reproduce externally reported vulnerabilities against running product instances and validate patches before release. 

• Own the penetration testing program: scope and coordinate third-party engagements, perform targeted testing yourself, and validate findings through retesting.

• Run our Vulnerability Disclosure Program, including researcher communications and coordinated disclosure. 

• Coordinate the CVE lifecycle for Cleo products and support product-security incident response. 

• Own the application and product-security controls in Cleo's NIST CSF 2.0 program: track maturity, close gaps, and produce the evidence our audits rely on. 

Product security 

• Own the security posture of the products Cleo ships, across SaaS and customer-hosted deployment models: secure defaults, authentication and session controls, RBAC and tenant isolation, admin data access, security-relevant configuration, and hardening guidance for customers. 

• Own the Product Security Roadmap: partner with Product Management, the CTO, and Architecture to get security features prioritized and shipped, including SSO/SAML upgrades, the in-app RBAC redesign, endpoint-level access control, and customer-requested controls, and represent security in RTE Sync and Boundary Review. 

• Be the technical owner for customer-facing product security: triage customer vulnerability-scan findings and penetration-test reports against Cleo products, answer security RFIs and enhancement requests, and author customer-facing advisories, security release notes, and hardening documentation. 

AI Fluency Competencies

• Own threat modeling and security review for LLM-enabled product features, AI agents, and AI-assisted development workflows. 
• Build controls and secure patterns for prompt injection, sensitive data exposure, insecure output handling, excessive agency, insecure tool integrations, and AI supply-chain risk. 
• Apply and operationalize the OWASP Top 10 for LLM Applications and the NIST AI Risk Management Framework across product and engineering. 

Prerequisites

• 6+ years in application security, product security, or secure software engineering, including experience building or maturing an AppSec program across multiple engineering teams. 

• Strong object-oriented developer: Strong proficiency in an object-oriented programming language is required, with Java preferred given Cleo’s core products are Java-based. You should be able to read, debug, and write production-quality code and be comfortable working across languages such as TypeScript, Python, or Go. 

• Deep knowledge of application attack surfaces: authentication, authorization, API security, business-logic flaws, and modern service architectures. 

• Hands-on experience integrating and tuning SAST, SCA, and secrets scanning in GitHub and CI/CD pipelines. 

• Hands-on exploit reproduction and patch validation: you can take a researcher's report of a pre-authentication vulnerability, reproduce it against a running Java web application, confirm the fix, and write up what the researcher and the customer each need to hear. 

• Coordinated disclosure experience with external security researchers and customers, including holding an embargo timeline and driving a CVE to publication. 

• Product security experience on shipped software with an installed base: secure defaults and hardening guidance, customer-facing advisories and security release notes, and turning a customer's scan report or RFI into a fix-or-explain response.