Secuno
ENNL
Book demo

CVE-2026-48039

Meta Ads MCP authentication bypass

9.1 CRITICALEPSS 0.59%
  1. Published7 Aug 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

CVE-2026-843138.8
Nginx UI is a web user interface for the Nginx web server. Prior to 2.4.1, POST…
CVE-2026-1093728.7
ZITADEL 4.x before 4.19.2 and 3.x through 3.4.15 contains an authentication bypass in…
CVE-2026-1093138.1
Grav Login plugin 2.7.0 before 3.9.9 contains an authentication bypass vulnerability…
CVE-2026-1093128.1
Grav Login plugin 2.7.0 before 3.9.9 contains an authentication bypass in…
CVE-2026-10890710.0
A vulnerability was determined in Netcore NR268 1.7.121109. Affected is the function…
CVE-2026-1088658.2
AmoyLab Unla through 0.10.0 contains an authentication bypass vulnerability that allows…

Frequently asked

Is CVE-2026-48039 being actively exploited?

CVE-2026-48039 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.59%.

How severe is CVE-2026-48039?

CVE-2026-48039 has a CVSS 3.1 base score of 9.1, rated critical. EPSS estimates a 0.59% probability of exploitation.

How do I fix CVE-2026-48039?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-48039 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

See how prioritisation worksBook a demo

Get Patch this first every Monday

Five vulnerabilities that matter this week, ranked on real exploitation. Plain language, one email, no spam.

You can unsubscribe with one click from every issue. We handle your details as described in our privacy policy.

Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.