Vulnerability · Published May 28, 2026 · Assigned by GitHub_M
CVE-2026-45366typescript-utcp: SSRF via attacker-controlled OpenAPI servers[0].url in HTTP communication protocol
Medium 4.7
In plain English
A medium-severity server-side request forgery in typescript-utcp from universal-tool-calling-protocol. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @utcp/http | 1.1.2 | GHSA-r8j5-8747-88cm |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| universal-tool-calling-protocol | typescript-utcp | < 1.1.2 |
Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N