CVE-2026-81098 — Telnyx MCP Server through 6.83.0 Missing Authentication on Streamable HTTP Transport
The Telnyx MCP server exposed its HTTP transport on every interface and did not require a caller credential. packages/mcp-server/src/http.ts served MCP on the root path with a l…
Published: 2026-08-27 · CVSS: 9.3 · CVSS 4.0
The Telnyx MCP server exposed its HTTP transport on every interface and did not require a caller credential. packages/mcp-server/src/http.ts served MCP on the root path with a listener bound to all interfaces and parsed the caller's authentication headers in a mode that did not fail when they were absent, so a request without any credential completed initialisation and dispatched tools. Dispatch forwarded the server's own stored credentials, the Telnyx API key and client secret together with the code-execution key, to the upstream endpoint, so an unauthenticated caller able to reach the port acted with them. The current code defaults the host to loopback, requires a server API key, and enforces it in middleware.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7