Security Engineer Intern (Summer 2026)

Summary: Poshmark is the leading fashion marketplace where style comes alive through discovery, self-expression, and human connection. The Product Security Intern will work alongside experienced security engineers to identify vulnerabilities and support secure development practices, contributing to the integrity of Poshmark's platform. Responsibilities: - Conduct vulnerability assessments and assist with penetration testing across Poshmark's web and mobile product surfaces - Perform secure code reviews to identify common security weaknesses (e.g., OWASP Top 10) within the software development lifecycle and help improve documentation - Assist in triaging and documenting findings from SAST/DAST tooling, working with engineering teams to prioritize remediation - Collaborate with software engineers to promote security best practices - Support the creation or improvement of internal security documentation, guidelines, and developer-facing checklists - Help track and manage vulnerability findings and remediation workflows in JIRA Required Qualifications: - Currently pursuing a bachelor's degree in computer science, computer engineering, Information Security, cybersecurity, or a related field - Foundational understanding of web application security concepts and common vulnerability classes - Familiarity with secure coding practices and the software development lifecycle - Ability to communicate technical findings clearly in written and verbal form - Demonstrated interest in Poshmark's mission, community, or industry - Current or rising senior enrolled in an accredited university, or recent college graduate - Seniors should expect to graduate between Fall 2026 and Summer 2027 - Strong communication, collaboration, and curiosity - Available to work a M-F 5-day work schedule between 8am-5pm - Willing to commute 5x per week to PMHQ in Redwood City, CA - No employment sponsorship required now or in the future Required Skills: Vulnerability Assessment, Penetration Testing, Web Application Security, Secure Coding Practices, Software Development Lifecycle, Static Application Security Testing (SAST), Dynamic Application Security Testing (DAST), Security Documentation, JIRA Internship Start Date: Start in 2026 Summer