GHSA-45gf-fjxp-cjpq

Server-Side Request Forgery (SSRF) in upload_ad_image via Unrestricted image_url Fetch

Summary

The upload_ad_image MCP tool in meta-ads-mcp v1.0.113 passes an attacker-controlled image_url parameter directly to an HTTP fetch helper (httpx.AsyncClient(follow_redirects=True).get(url)) without any scheme, host, or IP address validation. When the server is deployed with the streamable-http transport (a documented, officially supported mode), an unauthenticated remote attacker can supply an arbitrary URL—including http://127.0.0.1/, RFC 1918 addresses, or cloud metadata endpoints such as http://169.254.169.254/—and cause the server to issue an outbound HTTP request to that target. The Authorization middleware only verifies that a non-empty Bearer token is present; actual Meta API credential validation occurs after the image download, so any dummy Bearer token bypasses the pre-fetch check. This constitutes a full, unauthenticated Server-Side Request Forgery with a confirmed CVSS 3.1 Base Score of 8.3 (High).

Details

Source

meta_ads_mcp/core/ads.py, line 1316–1322: The MCP tool upload_ad_image is registered with @mcp_server.tool() and exposes image_url: Optional[str] as a direct tool argument that is fully attacker-controlled over the network.

# meta_ads_mcp/core/ads.py
1316: @mcp_server.tool()
1318: async def upload_ad_image(
1322:     image_url: Optional[str] = None,

Propagation

meta_ads_mcp/core/ads.py, line 1389: The value is forwarded to try_multiple_download_methods(image_url) without any sanitization or validation.

# meta_ads_mcp/core/ads.py
1389:     image_bytes = await try_multiple_download_methods(image_url)

Sinks

meta_ads_mcp/core/utils.py contains three independent HTTP fetch paths, all using httpx.AsyncClient with follow_redirects=True and no URL, host, or IP validation:

# meta_ads_mcp/core/utils.py
166:     async with...