CVE-2026-35577
Missing Host Header Validation in Apollo MCP Server for Localhost Deployments
Description
Apollo MCP Server is a Model Context Protocol server that exposes GraphQL operations as MCP tools. Prior to version 1.7.0, the Apollo MCP Server did not validate the Host header on incoming HTTP requests when using StreamableHTTP transport. In configurations where an HTTP-based MCP server is run on localhost without additional authentication or network-level controls, this could potentially allow a malicious website—visited by a user running the server locally—to use DNS rebinding techniques to bypass same-origin policy restrictions and issue requests to the local MCP server. If successfully exploited, this could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the local user. This issue is limited to HTTP-based transport modes (StreamableHTTP). It does not affect servers using stdio transport. The practical risk is further reduced in deployments that use authentication, network-level access controls, or are not bound to localhost. This vulnerability is fixed in 1.7.0.
INFO
Published Date :
April 9, 2026, 8:16 p.m.
Last Modified :
Oct. 26, 2026, 10:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update Apollo MCP Server to version 1.7.0 or later.
- Configure network-level access controls.
- Implement authentication for MCP server.
- Avoid binding the server to localhost.
Public PoC/Exploit Available at Github
CVE-2026-35577 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-35577.
| URL | Resource |
|---|---|
| https://github.com/apollographql/apollo-mcp-server/pull/602 | Issue Tracking |
| https://github.com/apollographql/apollo-mcp-server/pull/635 | Issue Tracking |
| https://github.com/apollographql/apollo-mcp-server/security/advisories/GHSA-wqrj-vp8w-f8vh | Mitigation Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-35577 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-35577
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
The Project shares all information on MCP related CVE's published
mcp mcp-security mcp-cve
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-35577 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-35577 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 26, 2026
Action Type Old Value New Value Added Translation Title: apollo-mcp-server de apollographql, Description: Apollo MCP Server es un servidor de Protocolo de Contexto de Modelo que expone operaciones GraphQL como herramientas MCP. Antes de la versión 1.7.0, el servidor Apollo MCP no validaba el encabezado Host en las solicitudes HTTP entrantes cuando utilizaba el transporte StreamableHTTP. En configuraciones donde un servidor MCP basado en HTTP se ejecuta en localhost sin autenticación adicional o controles a nivel de red, esto podría permitir potencialmente que un sitio web malicioso -visitado por un usuario que ejecuta el servidor localmente- utilice técnicas de reencuadernación de DNS para eludir las restricciones de la política del mismo origen y emitir solicitudes al servidor MCP local. Si se explota con éxito, esto podría permitir a un atacante invocar herramientas o acceder a recursos expuestos por el servidor MCP en nombre del usuario local. Este problema se limita a los modos de transporte basados en HTTP (StreamableHTTP). No afecta a los servidores que utilizan el transporte stdio. El riesgo práctico se reduce aún más en implementaciones que utilizan autenticación, controles de acceso a nivel de red o no están vinculadas a localhost. Esta vulnerabilidad se corrige en la versión 1.7.0. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'apollographql', 'product': 'apollo-mcp-server', 'versions': [{'status': 'affected', 'version': '< 1.7.0'}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-35577', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-04-13T15:05:51.571445Z'} -
Initial Analysis by [email protected]
Apr. 17, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N Added CPE Configuration OR *cpe:2.3:a:apollographql:apollo_mcp_server:*:*:*:*:*:*:*:* versions up to (excluding) 1.7.0 Added Reference Type GitHub, Inc.: https://github.com/apollographql/apollo-mcp-server/pull/602 Types: Issue Tracking Added Reference Type GitHub, Inc.: https://github.com/apollographql/apollo-mcp-server/pull/635 Types: Issue Tracking Added Reference Type GitHub, Inc.: https://github.com/apollographql/apollo-mcp-server/security/advisories/GHSA-wqrj-vp8w-f8vh Types: Mitigation, Vendor Advisory -
New CVE Received by [email protected]
Apr. 09, 2026
Action Type Old Value New Value Added Description Apollo MCP Server is a Model Context Protocol server that exposes GraphQL operations as MCP tools. Prior to version 1.7.0, the Apollo MCP Server did not validate the Host header on incoming HTTP requests when using StreamableHTTP transport. In configurations where an HTTP-based MCP server is run on localhost without additional authentication or network-level controls, this could potentially allow a malicious website—visited by a user running the server locally—to use DNS rebinding techniques to bypass same-origin policy restrictions and issue requests to the local MCP server. If successfully exploited, this could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the local user. This issue is limited to HTTP-based transport modes (StreamableHTTP). It does not affect servers using stdio transport. The practical risk is further reduced in deployments that use authentication, network-level access controls, or are not bound to localhost. This vulnerability is fixed in 1.7.0. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N Added CWE CWE-346 Added Reference https://github.com/apollographql/apollo-mcp-server/pull/602 Added Reference https://github.com/apollographql/apollo-mcp-server/pull/635 Added Reference https://github.com/apollographql/apollo-mcp-server/security/advisories/GHSA-wqrj-vp8w-f8vh