๐Ÿ” CVE Alert

CVE-2026-81098

CRITICAL 9.1

Telnyx MCP Server through 6.83.0 Missing Authentication on Streamable HTTP Transport

CVSS Score
9.1
EPSS Score
0.0%
EPSS Percentile
0th

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.

CWE CWE-306
Vendor team-telnyx
Product telnyx-mcp
Published Aug 27, 2026
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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

Affected Versions

team-telnyx / telnyx-mcp
0 โ‰ค 6.83.0

References

NVD โ†— CVE.org โ†— EPSS Data โ†—
github.com: https://github.com/team-telnyx/telnyx-node github.com: https://github.com/team-telnyx/telnyx-node/pull/450 github.com: https://github.com/team-telnyx/telnyx-node/security/advisories/GHSA-46jp-xr2h-fw7h vulncheck.com: https://www.vulncheck.com/advisories/telnyx-mcp-server-through-6.83.0-missing-authentication-on-streamable-http-transport

Credits

Avishai Gonen (Pluto Security)