How SSVC & CSAF Improve Vulnerability Management
In today's cybersecurity landscape, organizations must prioritize vulnerabilities efficiently to minimize risk. Learn how SSVC (Stakeholder-Specific Vulnerability Categorization) and CSAF (Common Security Advisory Framework) enhance vulnerability management beyond traditional CVSS ratings, which often lack the necessary context for effective vulnerability remediation. When it comes to managing vulnerabilities, your company can improve cybersecurity risk management through automation and smarter prioritization using these tools.
Understanding SSVC
What is SSVC?
Stakeholder-Specific Vulnerability Categorization (SSVC) is a decision-making framework that helps organizations prioritize and manage cybersecurity threats based on the specific situation of an organization. Unlike CVSS, which provides a numerical severity score, SSVC uses decision trees to classify vulnerabilities into one of four priority levels: Defer, Scheduled, Out-of-Cycle, or Immediate.
The SSVC decision points include:
- Exploitation status: Is the vulnerability actively exploited?
- System exposure: How critical is the affected system and what’s its impact to the rest of the organization?
- Utility: How easily can the vulnerability be automated or scaled?
- Human impact: Does the vulnerability impact critical infrastructure or human safety?
By combining these factors, organizations can determine the best course of action.
Using SSVC for Prioritization
Cyber threats are evolving rapidly, and organizations need a structured way to respond to them. SSVC helps decision-makers avoid guesswork by providing a clear, logical system to determine how urgent a cybersecurity issue really is and what action should be taken. Here’s how we’ve implemented SSVC in our platform:
- Assess the vulnerability: Gather details such as CVSS score, affected systems, and exploitability.
- Apply the SSVC decision tree: Use predefined decision points to categorize vulnerabilities based on organizational risk.
- Determine the response: Given the output of the SSVC model, work is categorized into the following:
- Defer – No immediate action is needed.
- Scheduled – The fix can wait until the next regular maintenance period.
- Out-of-Cycle – The fix should be done sooner than usual but in a controlled way.
- Immediate – A critical threat that requires urgent action.
Using a framework like this makes vulnerability prioritization more repeatable and easily scaled across the complexity of OT systems. It also creates logic that can be referenced in reporting compliance.
And we are not alone in using this framework — Cybersecurity and Infrastructure Security Agency (CISA) encourages organizations to improve risk-based vulnerability management by incorporating decision trees into their cybersecurity workflows.
Understanding CSAF
What is CSAF?
Common Security Advisory Framework (CSAF) is a standardized format for publishing security advisories in a machine-readable way. It allows organizations to automate vulnerability intake, reducing manual effort in tracking security updates from vendors.
Key CSAF benefits include:
- Automation: Security advisories can be parsed and processed automatically.
- Interoperability: Works across different security tools and platforms.
- Consistency: Provides structured, detailed security advisory information.
CSAF provides a structured, machine-readable format (JSON) for publishing and consuming security advisories. The “extra” remediation data found in security advisories and reportable in CSAF tells operators what can be done about a vulnerability after prioritization using SSVC.
Leveraging CSAF for Automation
First, a bit of background: CVE (Common Vulnerabilities and Exposures) Numbering Authorities, or CNAs, are organizations authorized to publish a CVE record for products within a particular scope. If the CNA is a vendor, the scope will typically encompass vulnerabilities for their products; i.e., if a CNA, a vendor has primary authority and responsibility for publishing vulnerabilities found in their products.
One requirement for becoming a CNA is having a public source for vulnerability disclosures. For many vendors, security advisories act as that vulnerability disclosure source. This is so frequent that the official CNA list includes a “View Advisories” link for each CNA.
Advisories often contain details not found in the National Vulnerability Database (NVD), because the CVE standard is primarily designed to communicate vulnerability information. Remediation details are, by nature, platform-specific, and this information is left to the vendors to communicate. Vendor security advisories, then, may contain mitigation or workaround instructions, patch details, security best practices, or additional criteria for applicability.
Advisories are typically published as PDF or HTML. When they do include a machine-readable format, it is often the CVE record JSON or, occasionally, the Vulnerability Exploitability eXchange (VEX). The VEX standard helps communicate if one or more products is affected by one or more vulnerabilities, but it doesn’t easily accommodate remediation details. When security operators need details of vulnerability remediation, they still must find those manually.
That’s where CSAF comes in — by providing advisories in this detailed, standardized format, vendors can support the automation of vulnerability and remediation management, allowing customers and consumers to address security issues more quickly. This enables the automation of importing vulnerability information and remediation steps, which allows for faster analysis (whether manual or automated) and reduces the need for manual effort in making remediation decisions.
As of March 31, 2025, there are 447 CNAs, and we are aware of 18 who provide their advisories in CSAF. We need greater industry adoption of this framework.
CISA also urges cybersecurity teams to adopt CSAF and stay ahead of threats by streamlining advisory distribution, increasing clarity, and enabling automation with consistent formatting.
How CSAF and SSVC Can Work Together to Level Up Remediation Management
By integrating SSVC’s structured decision-making with CSAF’s automated advisory processing, organizations can significantly improve their vulnerability management processes. SSVC ensures that vulnerabilities are prioritized effectively, while CSAF streamlines advisory handling, reducing manual workload. Together, these two tools can significantly speed up decision making and ultimately, reduce more risk.
Organizations looking to strengthen their cybersecurity posture should consider adopting SSVC and CSAF as part of their vulnerability management strategy.
