---
id: GHSA-v3f4-w7r7-v3hm
title: >-
  Uni-CLI: Legacy HTTP MCP transport accepted browser-originated localhost
  requests
summary: >-
  Uni-CLI: Legacy HTTP MCP transport accepted browser-originated localhost
  requests
severity: high
cwe:
  - CWE-346
  - CWE-352
vendor: zenalexa
product: '@zenalexa/unicli'
ecosystem: npm
affected:
  - '@zenalexa/unicli < 0.225.2'
patched:
  - '@zenalexa/unicli 0.225.2'
published: '2026-06-19'
updated: '2026-06-19'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-v3f4-w7r7-v3hm'
references:
  - url: >-
      https://github.com/olo-dot-io/Uni-CLI/security/advisories/GHSA-v3f4-w7r7-v3hm
  - url: 'https://github.com/advisories/GHSA-v3f4-w7r7-v3hm'
tags:
  - ghsa
  - npm
ingestedAt: '2026-06-22T13:35:24.232Z'
---

## Overview

## Impact

Uni-CLI versions before 0.225.2 exposed the legacy JSON-RPC-over-HTTP MCP transport on loopback without validating browser Origin headers before routing requests. A malicious web page could send a CORS simple POST request, such as text/plain, to the local /mcp endpoint and deliver a JSON-RPC body to the dispatcher. If the user had started the local MCP HTTP transport, that page could drive tools/call requests against the user's local Uni-CLI server.

The Streamable HTTP transport already enforced this browser-to-localhost boundary. The legacy stateless HTTP path did not, so the two HTTP transports had drifted. This issue is about the browser-to-localhost boundary; it does not change Uni-CLI's local-code-execution trust model.

## Patches

Version 0.225.2 fixes the issue by moving the Origin policy into a shared guard and applying it before routing in both HTTP transports. Non-loopback browser Origins are rejected with HTTP 403 before health, OAuth, or /mcp dispatch runs. Non-browser clients that omit Origin remain supported.

## Workarounds

Upgrade to 0.225.2 or later. If upgrading is not immediately possible, do not expose the legacy HTTP MCP transport to browser-originated traffic; use the default stdio transport or the Streamable HTTP transport instead.

## Credits

Reported privately by Ryan Vonbrubeck ([@dodge1218](https://github.com/dodge1218)).

## Affected packages

- `@zenalexa/unicli < 0.225.2`

## Remediation

Upgrade to a patched release:

- `@zenalexa/unicli 0.225.2`