---
id: CVE-2026-101059
title: >-
  utcp-http before 1.1.4 fails to validate the OAuth2 tokenUrl field from remote
  OpenAPI specifications, allowing attackers to redirect credential submission
  to arbitrary endpoints
summary: >-
  utcp-http before 1.1.4 fails to validate the OAuth2 tokenUrl field from remote
  OpenAPI specifications, allowing attackers to redirect credential submission
  to arbitrary endpoints. When a victim registers an attacker-controlled OpenAPI
  sp…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N'
cwe:
  - CWE-918
vendor: universal-tool-calling-protocol
product: python-utcp
affected:
  - python-utcp < 1.1.4
published: '2026-09-27'
updated: '2026-09-27'
sourceUpdated: '2026-09-27T18:16:32.130'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-101059'
references:
  - url: >-
      https://github.com/universal-tool-calling-protocol/python-utcp/security/advisories/GHSA-8cp3-qxj6-px34
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/utcp-http-before-1.1.4-oauth2-tokenurl-trust-boundary-bypass
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-27T17:56:02.208Z'
---

## Overview

utcp-http before 1.1.4 fails to validate the OAuth2 tokenUrl field from remote OpenAPI specifications, allowing attackers to redirect credential submission to arbitrary endpoints. When a victim registers an attacker-controlled OpenAPI spec and invokes a generated OAuth2-protected tool, the library POSTs the victim's client_id and client_secret to the attacker-supplied token endpoint without URL validation.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.