Security Digest · Vulnerability record
CVE-2026-48039: Meta Ads MCP: Unauthenticated HTTP MCP Tool Execution Leaks Operator Meta Access Token
Meta Ads MCP is a Model Context Protocol (MCP) server that lets AI assistants run Meta Ads.
CVSS 9.1 Critical EPSS 0.6% · p47
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.6%, percentile 47: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 47% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
meta-ads-mcp(PyPI) <= 1.0.108, fixed in 1.0.109. Check your lockfile, including transitive dependencies.
What it is
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 httpauthintegration.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 METAACCESSTOKEN 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 accesstoken as a query parameter—into the JSON-RPC response body, delivering the credential to the unauthenticated caller. Version 1.0.109 fixes the issue.
From the GitHub advisory
Unauthenticated HTTP MCP Tool Execution Leaks Operator Meta Access Token
| Field | Value | | ---------------- | ----- | | Repository | pipeboard-co/meta-ads-mcp | | Affected version | ≤ 1.0.101 (commit 496c988 ~ 7d14226); Versions 1.0.102–1.0.105 lack git tags, so patch status is unconfirmed. | | Vulnerability | CWE-287 — Improper Authentication | | Severity | Critical | | CVSS 3.1 | 9.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N) |
Summary
AuthInjectionMiddleware.dispatch() at httpauthintegration.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 METAACCESSTOKEN 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 accesstoken as a query parameter—into the JSON-RPC response body, delivering the credential to the unauthenticated caller.
Affected Code
Weakness type: CWE-287, CWE-209, CWE-522.
Product: meta-ads-mcp (PyPI) · Assigned by: GitHub_M · Published: 2026-08-07
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| PyPI | meta-ads-mcp | <= 1.0.108 | 1.0.109 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| pipeboard-co | meta-ads-mcp | < 1.0.109 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.1 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| GitHub | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.59% probability of exploitation activity in the next 30 days; percentile 47.
Timeline
- — GitHub-reviewed advisory GHSA-9gw6-46qc-99vr published (critical)
- — CVE record last updated
- — CVE record published by GitHub_M
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-9gw6-46qc-99vr github.com
- CVE.org record CVE-2026-48039 cve.org
- NVD entry CVE-2026-48039 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com