CVE-2026-81098

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.

CVSS v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/team-telnyx/telnyx-node
https://github.com/team-telnyx/telnyx-node/pull/450
https://github.com/team-telnyx/telnyx-node/security/advisories/GHSA-46jp-xr2h-fw7h
https://www.vulncheck.com/advisories/telnyx-mcp-server-through-6.83.0-missing-authentication-on-streamable-http-transport

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-27 17:20

Updated : 2026-08-27 20:18

NVD link : CVE-2026-81098

Mitre link : CVE-2026-81098

CVE.ORG link : CVE-2026-81098

JSON object : View

Products Affected

No product.

CWE

CWE-306

Missing Authentication for Critical Function

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