Hottest cybersecurity open-source tools of the month: May 2025
This month’s roundup features exceptional open-source cybersecurity tools that are gaining attention for strengthening security across various environments.
Vuls: Open-source agentless vulnerability scanner

Vuls is an open-source tool that helps users find and manage security vulnerabilities. It was created to solve the daily problems admins face when trying to keep servers secure.

LlamaFirewall: Open-source framework to detect and mitigate AI centric security risks

LlamaFirewall is a system-level security framework for LLM-powered applications, built with a modular design to support layered, adaptive defense. It is designed to mitigate a wide spectrum of AI agent security risks including jailbreaking and indirect prompt injection, goal hijacking, and insecure code outputs.

Hanko: Open-source authentication and user management

Hanko is an open-source, API-first authentication solution purpose-built for the passwordless era.

Cerbos: Open-source, scalable authorization solution

Cerbos is an open-source solution designed to simplify and modernize access control for cloud-native, microservice-based applications.

Must read:
- GitHub CISO on security strategy and collaborating with the open-source community
- Don’t let these open-source cybersecurity tools slip under your radar
- 33 open-source cybersecurity solutions you didn’t know you needed

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