CVE-2026-45366 MEDIUM

CVE-2026-45366: typescript-utcp: SSRF via attacker-controlled OpenAPI servers[0].url in HTTP communication protocol

Vendor Universal-Tool-Calling-Protocol
Product typescript-utcp
Weakness CWE-918 · SSRF
Published May 28, 2026
Last update May 29, 2026

CVSS base score

4.7/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction Required
Confidentiality Low
Integrity Low

CVSS vector

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

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

May 28, 2026 CVE published
May 29, 2026 Record updated

Related vulnerabilities

04Related CVE