CVE-2026-11720Critical· 9.1▾ MidnightMCP Toolbox HTTP tool path parameters allow traversal to unintended endpoints
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 50.1 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Sep 5.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
Last analysed / modified upstream
0.5%
A path traversal vulnerability exists in the HTTP tool URL builder of googleapis/mcp-toolbox.
When constructing downstream API requests, the URL builder substitutes user-controlled pathParams into the configured tool path and parses the resulting string as a relative URL. While it checks that the input does not alter the scheme, host, or user info, it relies on ResolveReference for the final URL resolution. Because dot segments (../) are normalized during this resolution step, an attacker can supply path parameters containing directory traversal sequences to escape the operator-configured path scope. This allows the client to coerce the toolbox into making requests to unintended endpoints on the same target host while forwarding the toolbox's configured credentials (e.g., bypassing a restricted path like /api/v1/users/{{.id}} to reach /admin/secrets).
github.com/googleapis/mcp-toolbox < 1.3.0Upgrade to a patched release:
github.com/googleapis/mcp-toolbox 1.3.0Connected by shared product, vendor, weakness, or advisory.
CVE-2026-11624CriticalMCP Toolbox for Databases has an Origin Validation Error
CVE-2026-11717Criticalgoogleapis/mcp-toolbox: authentication bypass vulnerability in the generic opaque token validation path (validateOpaqueToken)
CVE-2026-11718Criticalgoogleapis/mcp-toolbox: authentication bypass vulnerability in the generic opaque token validation path (validateOpaqueToken)
CVE-2026-11719HighMCP Toolbox for Databases: authenticated authorization bypass