CVE-2026-48039

Meta Ads MCP is a Model Context Protocol (MCP) server that lets AI assistants run Meta Ads. Prior to version 1.0.109, `AuthInjectionMiddleware.dispatch()` at `http_auth_integration.py:272` unconditionally forwards unauthenticated Streamable HTTP requests to downstream MCP tool handlers without issuing a `401` response, allowing any network-reachable caller to invoke MCP tools without authentication. When no per-request credential is present, tool handlers fall back to the `META_ACCESS_TOKEN` environment variable, and when the downstream Meta Graph API call fails, `api.py:263–269` serialises the raw `httpx` request URL—including the operator's `access_token` as a query parameter—into the JSON-RPC response body, delivering the credential to the unauthenticated caller. Version 1.0.109 fixes the issue.

Published 07 Aug 2026, 20:16 UTC Last modified 07 Aug 2026, 20:16 UTC

9.1

CVSS 3.1 CRITICAL base score CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack profile

The conditions required to exploit this vulnerability and its potential impact.

Attack vector Network

Attack complexity Low

Privileges required None

User interaction None

Scope Unchanged

Confidentiality High

Integrity High

Availability None

Exploitability3.9

Impact5.2

Affected products

Product applicability statements supplied with the NVD record.

NVD has not published structured affected-product data for this record.

Weakness classification

CWE categories help security teams group the underlying software weakness.

CWECWE-287

Source references

External advisories, patches and technical reports attached to this CVE record.

NVD National Vulnerability Database recordnvd.nist.gov 01 Technical reference security-advisories@github.com 02 Technical reference security-advisories@github.com 03 Technical reference security-advisories@github.com