---
id: CVE-2026-81098
title: >-
  The Telnyx MCP server exposed its HTTP transport on every interface and did
  not require a caller credential
summary: >-
  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
  auth…
severity: critical
cvss: 9.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-306
published: '2026-08-27'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T20:43:32.537'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-81098'
references:
  - url: 'https://github.com/team-telnyx/telnyx-node'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/team-telnyx/telnyx-node/pull/450'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/team-telnyx/telnyx-node/security/advisories/GHSA-46jp-xr2h-fw7h
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/telnyx-mcp-server-through-6.83.0-missing-authentication-on-streamable-http-transport
    label: disclosure@vulncheck.com
tags:
  - nvd
epss: 0.00727
epssPercentile: 0.52123
ingestedAt: '2026-09-24T20:51:40.235Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.