The get-html-skeleton tool fetched a URL the caller supplied after checking only its syntax. The handler in src/tools/common/get_html_skeleton.ts validated the url argument with isValidHttpUrl from src/utils/generic.ts, which confirmed the string began with an http or https scheme and parsed as a URL and inspected neither the host name nor the address it resolves to. Loopback, link-local and private ranges therefore passed, including the address cloud providers use to serve instance metadata. The unchecked URL was handed to the web-browser actor and the fetched document was returned in the tool response, so any caller of the MCP server could make it request an endpoint reachable only from the host and read the result, including instance credentials. Version 0.9.12 removes the tool.

CVE-2026-81093 describes a Server-Side Request Forgery (SSRF) vulnerability in the Apify MCP Server's get-html-skeleton tool. The tool accepted caller-supplied URLs and only validated their syntax (http/https scheme and parseable format) without inspecting the hostname or resolved IP address. This allowed loopback, link-local, and private IP ranges to pass validation, including cloud provider instance metadata endpoints (e.g., 169.254.169.254). Any caller of the MCP server could exploit this to make the server fetch internal-only endpoints and return the response, potentially exposing sensitive instance credentials and internal services. The vulnerability resided in src/tools/common/get_html_skeleton.ts using the isValidHttpUrl function from src/utils/generic.ts. The fix in version 0.9.12 removes the vulnerable tool entirely rather than patching the URL validation logic.