Directory CybersecurityVulnerability ManagementSubfinder

Subfinder

Open Source

About Subfinder

Subfinder is a command-line tool that finds a website's subdomains using passive online sources. ProjectDiscovery publishes it as one of its open-source tools. Many of its sources need API keys to return results. It can also be used as a Go library.

Who it is for

Penetration testers and bug bounty hunters.

From Subfinder's own website, read 2026-10-28. How we build listings.

How to evaluate Vulnerability Management

This is how the CIOPages Research Team evaluates this category. It is not an assessment of Subfinder. It comes from our Vulnerability Management Platforms buyer guide.

25%

Asset Discovery & Coverage

Authenticated and unauthenticated scanning, agent + agentless options, coverage of cloud and ephemeral workloads, containers/Kubernetes, OT/IoT, identity, external attack surface, and unmanaged/shadow assets — plus how it avoids blind spots between scan windows

25%

Prioritization Quality

Beyond CVSS: exploit-prediction scoring (EPSS), known-exploited intelligence (CISA KEV), in-the-wild and ransomware association, exploit maturity, reachability/exploitability, and business asset criticality — the “which findings actually matter” engine and how transparent and tunable its scoring is

20%

Remediation & Workflow

Ticketing and ITSM integration (ServiceNow, Jira), patch-management hooks, remediation grouping by fix, SLA tracking, owner assignment, change-ticket automation, and closed-loop verification that a fix actually landed — not just that a ticket closed

15%

Exposure Context & Validation

Attack-path analysis and choke-point identification, unification of vuln + misconfiguration + identity findings, and validation that an exposure is genuinely reachable (control checks, exploitability confirmation) so the priority list reflects real risk, not theoretical severity

10%

Integration & Data Aggregation

Open API depth, ingestion of third-party scanner and CNAPP findings, de-duplication and normalization across tools, SIEM/SOAR and CMDB connectors, and how cleanly it fits an existing security stack rather than demanding rip-and-replace

Reporting & Program Metrics

Executive and board-ready risk reporting, trend lines on mean-time-to-remediate and risk burndown, SLA and compliance attestation (PCI, HIPAA, FedRAMP), and role-based views that hold owners accountable

Other Vulnerability Management Vendors

Maps an organization’s external attack surface, including subsidiaries and third-party dependencies, confirms which exposures are exploitable, and helps fix them.

Ivanti Neurons for RBVM

Kenna Security (Cisco)

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