What’s Vulnerable › Vulnerabilities
CVE-2026-14539: Denial of Service via Unrestricted Payload Buffering in MCP Toolbox
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-07-31 · updated 2026-10-23
- Weakness: CWE-770
Description
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.
Affected products
- Google MCP Toolbox for Databases (googleapis/mcp-toolbox): before 1.5.0 — fixed in 1.5.0
How to fix
Upgrade to a fixed version: Google MCP Toolbox for Databases (googleapis/mcp-toolbox) 1.5.0. Check the vendor advisory for mitigations.
References
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