VulnSocial

CVE-2025-66416Disclosure(lfprojects / mcp_python_sdk)

LOWCVSS 8.1 · HIGH

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD description

The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to version 1.23.0, tThe Model Context Protocol (MCP) Python SDK does not enable DNS rebinding protection by default for HTTP-based servers. When an HTTP-based MCP server is run on localhost without authentication using FastMCP with streamable HTTP or SSE transport, and has not configured TransportSecuritySettings, a malicious website could exploit DNS rebinding to bypass same-origin policy restrictions and send requests to the local MCP server. This could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the user in those limited circumstances. Note that running HTTP-based MCP servers locally without authentication is not recommended per MCP security best practices. This issue does not affect servers using stdio transport. This vulnerability is fixed in 1.23.0.

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0.0/ 10 priority

Sources & remediation

Patch / fix
Vendor / third-party advisories
Weakness type (CWE)
CWE-1188

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

NONE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • mcp_python_sdk

Threat summary

  • 1 mentions across 1 observed day

What's happening

  • Disclosure: 1 classified signal
  • 1 total mentions across 1 day

Affected systems

Vendors
lfprojects
Products
mcp_python_sdk

Deep dive

Activity timeline1 mentions / 1d
00111Mentions · 2026-04-11: 104-11
Signal classification1 categories
Disclosure
1100.0%
Referenced assets1 URL
By indicator
Full discourse1 post
  • Veros@boldnames
    Disclosure

    Don't just take my word for it, verify. We scanned a trending public Github repository by @Microsoft at microsoft/markitdown and found 2 critical OSVs interlinked to 6 CVEs, among other findings: https://github.com/microsoft/markitdown Dependencies: Pillow>=9.0.0 -> CVE-2023-50447, CVE-2024-28219, CVE-2023-44271. mcp~=1.8.0 -> CVE-2025-53366, CVE-2025-66416, CVE-2025-53365. Per this post, the dependency still exist at > >markitdown-ocr/pyproject.toml >markitdown-mcp/pyproject.toml

    Post summary

    The announcement identifies two critical OSVs linked to six CVEs within a public Microsoft GitHub repository, but it offers no exploitation details, patches, or additional technical specifics.

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CPE platform detail1 entries

1 of 1 entries

PartVendorProductVersionTarget SWTarget HW
Applfprojectsmcp_python_sdk---

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