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Critical CVSS 9.1

CVE-2026-48039

NVD analysis in progress

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.

What this means

Exposure
Exploitable remotely over the network, without authentication and with no action from the victim.
Impact
An attacker can read sensitive data and modify or destroy data.
Weakness
The authentication mechanism can be bypassed, letting an attacker pose as a legitimate user.
Likelihood
Its EPSS score stays low: nothing points to imminent exploitation, which is no reason to leave it unpatched.

What to doPatch without waiting for the next scheduled cycle. Start with the instances exposed to the internet.

Read automatically from the CVSS vector, the weakness type (CWE) and the EPSS score. The technical description above remains the one published by NIST.

Published
7 August 2026
CVSS
9.1 (v3.1) CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS
0.34% probability of exploitation within 30 days · above 27% of all CVEs
Weakness
CWE-287
Sources
nvd
References

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