Google mcp-toolbox up to 1.4.0 HTTP Client http.go server-side request forgery

Summaryinfo

A vulnerability marked as critical has been reported in Google mcp-toolbox up to 1.4.0. Impacted is an unknown function of the file internal/sources/http/http.go of the component HTTP Client. The manipulation leads to server-side request forgery. This vulnerability is listed as CVE-2026-14540. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in Google mcp-toolbox up to 1.4.0. It has been rated as critical. This issue affects an unknown code of the file internal/sources/http/http.go of the component HTTP Client. The manipulation with an unknown input leads to a server-side request forgery vulnerability. Using CWE to declare the problem leads to CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

A Server-Side Request Forgery (SSRF) vulnerability exists in the generic HTTP source and tool components of Google mcp-toolbox versions 0.3.0 through 1.4.0. While the toolbox implements baseline input sanitization for user-controlled parameters, the underlying HTTP client (internal/sources/http/http.go) fails to safely regulate request redirection boundaries. Specifically, the client is initialized without a restrictive CheckRedirect policy hook and lacks target IP validation. An attacker or a malicious data-driven prompt can supply a crafted path parameter that triggers an open redirect or a direct destination swap on the target backend, coercing the mcp-toolbox into blindly following the redirection and making unauthorized requests to internal or arbitrary external endpoints.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-14540 since 07/03/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/31/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Artificial Intelligence Software

Vendor

• Google

Name

• mcp-toolbox

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4.0

License

• free

Website

• Vendor: https://www.google.com/

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