Security Advisory: Critical Vulnerability in MCP HTTP Server Allows Unauthenticated Access (CVE-2026-81735)
Overview
A critical-severity vulnerability (CVE-2026-81735) has been identified affecting mcp-http-server, mcp-server-commands, mcp-server-filesystem, startserver.ts, ui-tars-desktop. Organizations should review their exposure and apply available patches immediately.
Technical Analysis
startServer.ts in the mcp-http-server package of UI-TARS-desktop defaulted its listen address to '::' when no host was given, so startSseAndStreamableHttpMcpServer bound the Streamable HTTP and SSE MCP transports to every interface, and its authentication middleware was optional: middlewares are applied only when a caller supplies them. The @agent-infra/mcp-server-commands and @agent-infra/mcp-ser
Enterprise & DIB Impact
Organizations in regulated sectors and the Defense Industrial Base should treat this as high priority given the severity rating and potential for exploitation.
Recommended Actions
- Apply vendor patches immediately
- audit network exposure
- implement compensating controls
- monitor for exploitation indicators
- review incident response readiness
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