Risk-based prioritization

Vulnerability prioritization with CISA KEV and EPSS

A scan can return dozens of CVEs, and severity alone does not say which one to fix first. For eligible CVE findings, ScanTitan shows the CVSS severity next to two exploitation signals: CISA KEV, which records known exploitation, and FIRST EPSS, which estimates the probability that a CVE will be exploited. Together they help you decide what needs attention first.

  • CVSS severity
  • CISA KEV
  • FIRST EPSS

KEV and EPSS enrichment applies to eligible CVE findings when the intelligence is available. It is not a separate premium add-on.

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Three signals, three different questions

CVSS: how severe is it?

A score for the technical severity of a vulnerability. It describes the flaw, not whether anyone is attacking it.

CISA KEV: is it being exploited?

The Known Exploited Vulnerabilities catalog lists CVEs with evidence of exploitation. It records what has already happened.

FIRST EPSS: how likely is exploitation?

A model that estimates the probability that a published CVE will be exploited in the next 30 days.

Read the definitions from the sources: the CISA KEV catalog and the FIRST EPSS model. Each signal answers a different question, which is why a high CVSS score alone is a weak way to order a patching queue.

How to prioritize vulnerabilities with KEV and EPSS

  1. Start with KEV-listed CVEs. Known exploitation is the strongest reason to act now.
  2. Then look at high EPSS. A CVE that is not on KEV but has a high probability of exploitation deserves an early fix.
  3. Use CVSS and exposure for the rest. Severity, whether the service is reachable from the internet, and how important the asset is decide the order of everything else.
  4. Treat missing intelligence as missing. When KEV or EPSS data is unavailable, ScanTitan says so instead of implying a low risk.

This table is a reading guide. It is not a scan result.

What you seeHow to read it
Listed in KEVKnown exploitation exists. Fix first on any asset where the affected software is present and exposed.
High EPSS, not in KEVNo known exploitation record yet, but exploitation is likely. Fix soon.
High CVSS, low EPSS, not in KEVSevere flaw with little sign of attack. Schedule by exposure and asset importance.
Intelligence unavailableUse CVSS and exposure. Do not read the absence of a signal as safety.

Scope and limits

A score is a prioritization aid. It does not prove that your asset is being exploited.
  • It applies to eligible CVE findings when intelligence is available, for example version-matched advisories on public servers.
  • A high EPSS score or a KEV listing does not prove that your specific asset was or will be attacked.
  • Not being in KEV, or a low EPSS score, is not a guarantee of safety.
  • The intelligence date is shown where it is available.

Plans and where to start

The prioritization signals are not Business-only. Public server and IP assessments, where CVE matching is most common, are available with Business at $155 per asset place per year, and Consultant at $486 per asset place per year adds client reporting. See the pricing page for what each plan includes.

These findings appear in the network vulnerability scanner and IP vulnerability scanner results, and in the reports you export for clients through the Consultant plan.

Vulnerability prioritization questions

What is vulnerability prioritization?

It is ordering vulnerabilities by how urgently they need fixing, using more than severity alone. ScanTitan combines CVSS with CISA KEV and FIRST EPSS for eligible CVE findings.

What does CISA KEV mean?

KEV is the Known Exploited Vulnerabilities catalog. A CVE in it has evidence of real-world exploitation.

What does EPSS measure?

EPSS estimates the probability that a published CVE will be exploited in the next 30 days.

Does a high EPSS score mean my server will be attacked?

No. It describes how likely exploitation of the CVE is in general. It does not prove that your asset is targeted.

If a CVE is not in KEV, is it safe?

No. KEV lists known exploitation. A CVE missing from it may still be exploited or become exploited.

Which findings get KEV and EPSS data?

Eligible CVE findings, when the intelligence is available. Other findings do not carry these labels.

Is KEV and EPSS enrichment Business only?

No. It is part of the findings. Business adds public server assessments and Consultant adds client reporting.

Fix the right vulnerabilities first

See which plan fits the assets you need to assess, or try the CVE Priority Checker on a list of CVEs.

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