CVE-2026-45366 PUBLISHED

typescript-utcp: SSRF via attacker-controlled OpenAPI servers[0].url in HTTP communication protocol

Assigner: GitHub_M
Reserved: 12.05.2026 Published: 28.05.2026 Updated: 28.05.2026

typescript-utcp is a typescript implementation of UTCP. Prior to 1.1.2, the @utcp/http package is vulnerable to a blind Server-Side Request Forgery (SSRF) caused by a trust-boundary inconsistency between manual discovery and tool invocation. registerManual() validates the discovery URL against an HTTPS / loopback allowlist, but callTool() reuses the resolved toolCallTemplate.url directly without revalidating, and the OpenApiConverter blindly trusts whatever servers[0].url an attacker-hosted spec declares. An attacker who hosts a malicious OpenAPI spec on a legitimate HTTPS endpoint can declare e.g. servers: [{ url: "http://127.0.0.1:9090" }] or servers: [{ url: "http://169.254.169.254" }]; the converter then produces tools whose URL points at internal services on the agent host. This vulnerability is fixed in 1.1.2.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS Score: 4.7

Product Status

Vendor universal-tool-calling-protocol
Product typescript-utcp
Versions
  • Version < 1.1.2 is affected

References

Problem Types

  • CWE-918: Server-Side Request Forgery (SSRF) CWE