CVE-2026-14539 — Denial of Service via Unrestricted Payload Buffering in MCP Toolbox
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…
Published: 2026-07-31 · CVSS: 6.6 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7