THREATPORT/VULNERABILITY/CVE-2025-53366
HIGH SEVERITY

CVE-2025-53366

CVE-2025-53366 vulnerability

Severity
HIGH
EPSS
5.7%
EPSS pct
92th
Exploited
No known
The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to version 1.9.4, a validation error in the MCP SDK can cause an unhandled exception when processing malformed requests, resulting in service unavailability (500 errors) until manually restarted. Impact may vary depending on the deployment conditions, and presence of infrastructure-level resilience measures. Version 1.9.4 contains a patch for the issue.
Affected vendor
See references
Affected product
See references
Weakness type (CWE)
Published
2025-07-04

Risk analysis

Its EPSS score of 5.7% reflects a lower probability of exploitation activity in the wild over the next 30 days, placing it above 92% of all scored CVEs.

Check your external exposure to CVE-2025-53366

  • Confirm whether the affected software is running on any internet-facing host or subdomain.
  • Match discovered service fingerprints against the version affected by CVE-2025-53366.
  • Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2025-53366

ThreatPort's external attack surface scanner checks your internet-facing assets — agentlessly, from the outside in — for the exposed services and versions that CVE-2025-53366 affects, then prioritises the finding by real risk using CISA KEV and FIRST.org EPSS.

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