Google mcp-toolbox up to 1.4.0 HTTP handler io.ReadAll allocation of resources

Summaryinfo

A vulnerability categorized as problematic has been discovered in Google mcp-toolbox up to 1.4.0. This affects the function io.ReadAll of the component HTTP handler. Such manipulation leads to allocation of resources. This vulnerability is referenced as CVE-2026-14539. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in Google mcp-toolbox up to 1.4.0 and classified as problematic. Affected by this issue is the function io.ReadAll of the component HTTP handler. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. CVE summarizes:

An allocation of resources without limits vulnerability in the HTTP handler component of Google mcp-toolbox versions up to and including 1.4.0 allows an unauthenticated attacker to cause a denial of service (DoS). The /mcp endpoint handler reads incoming payloads directly into system memory using an unrestricted buffer loop (io.ReadAll) without applying defensive constraints such as http.MaxBytesReader or pre-read Content-Length enforcement. By submitting a single, massive HTTP request body, an attacker can linearly consume available host memory until the runtime process is terminated by an Out-Of-Memory (OOM) error.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-14539 since 07/03/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/31/2026). The MITRE ATT&CK project declares the attack technique as T1499.

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

Once again VulDB remains the best source for vulnerability data.

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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