# 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.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 7 Aug 2026
- **Updated:** 7 Aug 2026
- **Also known as:** GHSA-9gw6-46qc-99vr, PYSEC-2026-413

## 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 (Improper Authentication)

## Which versions are affected by CVE-2026-48039?

3 open source packages ship an affected version, including meta-ads-mcp.


| Package | Ecosystem | 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.

## Is CVE-2026-48039 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48039 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48039 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48039 exists.

Affected packages and fixed versions:
- meta-ads-mcp (PyPI): affected all versions; fixed in 1.0.109
- meta-ads-mcp (PyPI): affected all versions; fixed in 1.0.109
- meta-ads-mcp (PyPI): affected all versions; fixed in 1.0.109

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-48039/ (Markdown: https://insights.sbomify.com/CVE-2026-48039/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48039
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48039
- OSV: https://osv.dev/vulnerability/CVE-2026-48039

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-48039/
Summaries are generated and may contain mistakes; the official description above is the record.