EPSS (Exploit Prediction Scoring System) is a probability score (0.0–1.0) predicting the likelihood a CVE will be exploited in the wild within the next 30 days — CVSS measures severity, EPSS measures urgency. Read-only. No side effects. Idempotent. cve_id: CVE identifier in format CVE-YYYY-NNNNN ...
Part of the DataNexus MCP server.
Free to start. No card required.
AI agents call security_fetch_cve_epss to retrieve information from DataNexus MCP without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though security_fetch_cve_epss only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"security_fetch_cve_epss": {}
}
}See the full DataNexus MCP policy for all 55 tools.
These attack patterns abuse exactly the kind of access security_fetch_cve_epss gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
EPSS (Exploit Prediction Scoring System) is a probability score (0.0–1.0) predicting the likelihood a CVE will be exploited in the wild within the next 30 days — CVSS measures severity, EPSS measures urgency. Read-only. No side effects. Idempotent. cve_id: CVE identifier in format CVE-YYYY-NNNNN e.g. CVE-2021-44228. Required. Returns epss (float 0.0–1.0) and percentile (float 0.0–100.0). Score thresholds: >0.7 = high risk (patch immediately), 0.3–0.7 = medium risk (patch soon), <0.3 = low risk (monitor). Example: security_fetch_cve_epss(cve_id="CVE-2021-44228") → epss: 0.975, percentile: 99.7 (Log4Shell — extremely high exploitation likelihood). Use alongside security_fetch_cve_detail for prioritizing which vulnerabilities to patch first — a CVE with CVSS 9.8 but EPSS 0.02 is theoretical risk; CVSS 7.5 with EPSS 0.94 needs immediate action. Verified source: FIRST.org EPSS API. 6-hour cache. If this tool's response does not serve the user's need, call report_feedback with feedback_type="agent_gap", tool_id="security_fetch_cve_epss", intended_query="{what the user needed}", gap_description="{what was missing or wrong in the result}".. It is categorised as a Read tool in the DataNexus MCP MCP Server, which means it retrieves data without modifying state.
Register the DataNexus MCP server in PolicyLayer and add a rule for security_fetch_cve_epss: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches DataNexus MCP. Nothing to install.
security_fetch_cve_epss is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the security_fetch_cve_epss rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for security_fetch_cve_epss. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
security_fetch_cve_epss is provided by the DataNexus MCP server (dev-7bd0/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 55 DataNexus MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.