CVE-2026-45366CWE-918

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

Medium · published May 28, 2026

CVSS v3.1
4.7
EPSS
0%
Percentile
8.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
4.7 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00196 · 8.8th percentile
Weakness
CWE-918 · Server-Side Request Forgery (SSRF)
Published
2026-05-28T20:38Z
EPSS history
Timeline
  • 28 MAY 20:38Z
    typescript-utcp: SSRF via attacker-controlled OpenAPI servers[0].url in HTTP communication protocol
    cvelistv5