CVE-2026-48039 Meta Ads MCP: Unauthenticated HTTP MCP Tool Execution Leaks Operator Meta Access Token
Unauthenticated attackers can invoke MCP tools and leak the operator's Meta access token due to missing authentication checks and verbose error handling.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-48039?
CVE-2026-48039 is a critical authentication bypass vulnerability in pipeboard-co meta-ads-mcp, published on 7 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-287
Which versions are affected by CVE-2026-48039?
3 open source packages ship an affected version, including meta-ads-mcp.
| Package | Affected | Fixed in |
|---|---|---|
meta-ads-mcp PyPI | All versions | 1.0.109 |
meta-ads-mcp PyPI | All versions | 1.0.109 |
meta-ads-mcp PyPI | All versions | 1.0.109 |
How do I fix CVE-2026-48039?
Upgrade meta-ads-mcp to 1.0.109 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-48039 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48039 exists.
Sources
Also known as GHSA-9gw6-46qc-99vr, PYSEC-2026-413.