GCD AI RADAR
incidents/AIR-2026-0806

CVE-2026-52869: MCP Python SDK HTTP transports fail to verify authenticated principal

Attack on AI2 Disclosed vulnerabilityInfrastructure vulnerability

The SSE and Streamable HTTP server transports in the MCP Python SDK route incoming session requests solely by session identifier without verifying the authenticated principal. Attackers who guess a session ID can send JSON-RPC messages across that session.

disclosed CVENo confirmed exploitation, so this record is tracked as a disclosed vulnerability and not counted as an incident. It moves into the counts if CISA or the vendor confirms exploitation. Why

Details

type
Attack on AI
An AI model, agent or AI-powered product was the thing exploited, abused or leaked.
categories
  • Infrastructure vulnerability
    CVEs and advisories in AI frameworks, inference servers, MCP servers, AI developer tools and hosting stacks.
owasp llm top 10
mitre atlas
no technique for these categories
Both rows are derived from the type and categories (OWASP 2025 edition, ATLAS release 2026.09), not classified per record. How
severity
2 · Disclosed vulnerability
CVE or vendor advisory, patched or patchable, no confirmed exploitation.
targets
Framework / tooling
products
MCP Python SDK
incident date
16 Jul 2026
first reported
15 Jul 2026
origin
GitHub Advisory Database
Vulnerability record from NVD / the GitHub Advisory Database. This product uses the NVD API but is not endorsed or certified by the NVD.
classifier confidence
0.95 · published at or above 0.80; see the methodology
tags
CVE-2026-52869 · mcp · authentication
record
created 2026-10-18 07:00Z · updated 2026-10-18 10:04Z · json

Sources · 2

  1. 2026-07-15
    CVE-2026-52869: The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP).
    NVD · nvd.nist.gov/vuln/detail/CVE-2026-52869
  2. 2026-07-16
    CVE-2026-52869: MCP Python SDK: HTTP transports serve session requests without verifying the authenticated principal
    GitHub Advisory Database · github.com/advisories/GHSA-jpw9-pfvf-9f58

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