CVE-2026-14540 Server-Side Request Forgery via Unrestricted HTTP Redirection in MCP Toolbox
Attackers can force the MCP Toolbox to make unauthorized requests to internal or external endpoints via unsafe HTTP redirection handling.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-14540?
CVE-2026-14540 is a high-severity server-side request forgery vulnerability in Google mcp-toolbox, published on 31 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-918
Which versions are affected by CVE-2026-14540?
It affects 1 product.
Products include Google Mcp Toolbox for Databases.
How do I fix CVE-2026-14540?
No fix has been published for CVE-2026-14540 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-14540 being exploited?
There is no known exploitation of CVE-2026-14540 in the wild and no public exploit code.
Other vulnerabilities in Google mcp-toolbox
- CVE-2026-11720 Path Traversal in googleapis/mcp-toolbox HTTP Tool URL Builder
- CVE-2026-11717 googleapis/mcp-toolbox: authentication bypass vulnerability in the generic opaque token validation path (validateOpaqueToken)
- CVE-2026-11718 googleapis/mcp-toolbox: authentication bypass vulnerability in the generic opaque token validation path (validateOpaqueToken)
- CVE-2026-15829 SQL Injection and Security Boundary Bypass in googleapis/mcp-toolbox
- CVE-2026-11719 MCP Toolbox for Databases: authenticated authorization bypass
Sources
Also known as GHSA-3x3x-8ffg-ghcv.