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CVE-2026-14539— Denial of Service via Unrestricted Payload Buffering in MCP Toolbox

Quick assessment

Affected
Google mcp-toolbox
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Google MCP Toolbox for Databases是美国Google公司的数据库管理工具。 Google MCP Toolbox for Databases 1.4.0及之前版本存在资源管理错误漏洞，该漏洞源于HTTP处理器组件中的/mcp端点处理程序使用无限制缓冲区循环（io.ReadAll）直接读取传入负载到系统内存，未应用http.MaxBytesReader或预先读取Content-Length等防御限制，可能导致未经身份验证的攻击者通过提交单个大型HTTP请求主体，线性消耗主机内存

CVSS 6.6 · Medium EPSS 0.24% · P14

Affected Version Matrix 1

VendorProduct Version RangeStatus
Google mcp-toolbox 0.0.0≤ 1.4.0 affected
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I. Basic Information for CVE-2026-14539

Vulnerability Information
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Vulnerability Title
Denial of Service via Unrestricted Payload Buffering in MCP Toolbox
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U
Source: CVE Program / CVE List V5
Vulnerability Type
不加限制或调节的资源分配
Source: CVE Program / CVE List V5
Vulnerability Title
Google MCP Toolbox for Databases 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Google MCP Toolbox for Databases是美国Google公司的数据库管理工具。 Google MCP Toolbox for Databases 1.4.0及之前版本存在资源管理错误漏洞，该漏洞源于HTTP处理器组件中的/mcp端点处理程序使用无限制缓冲区循环（io.ReadAll）直接读取传入负载到系统内存，未应用http.MaxBytesReader或预先读取Content-Length等防御限制，可能导致未经身份验证的攻击者通过提交单个大型HTTP请求主体，线性消耗主机内存
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Google mcp-toolbox 0.0.0 ~ 1.4.0 -

II. Public POCs for CVE-2026-14539

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III. Intelligence Information for CVE-2026-14539

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Patches & Fixes for CVE-2026-14539 (1)

Same Patch Batch · Google · 2026-07-31 · 5 CVEs total

CVE-2026-14537 8.1 HIGH Authorization Bypass in MCP Toolbox Legacy HTTP Endpoints
CVE-2026-14540 8.0 HIGH Server-Side Request Forgery via Unrestricted HTTP Redirection in MCP Toolbox
CVE-2026-14541 8.0 HIGH Authentication Bypass and Audience Confusion in MCP Toolbox OAuth Provider
CVE-2026-14538 5.7 MEDIUM BigQuery Dataset Allowlist Bypass via Metadata Dry-Run in MCP Toolbox

IV. Related Vulnerabilities

Same product: mcp-toolbox
Same vendor: Google
Same weakness: CWE-770

V. Comments for CVE-2026-14539

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