CVE-2026-58500

MCP Appium: Unescaped Locator Data XSS in MCP-UI Resource (createLocatorGeneratorUI)

Published Jul 13, 2026 CVSS 3.1 · 8.2 High EPSS < 1% KEV · Not listed
Description
MCP Appium is an MCP server that provides AI assistants with tools to automate mobile app testing on Android and iOS. In versions prior to 1.85.10, the createLocatorGeneratorUI function interpolates attacker-controlled element attributes — text, content-desc, resource-id, and locator selector values — directly into an HTML template literal without any HTML or JavaScript context escaping. An attacker who controls the UI of the app under test can inject arbitrary HTML and JavaScript into the MCP UI resource returned by the generate_locators tool. When a victim's MCP client renders this resource, the injected script executes and can invoke arbitrary MCP tools via window.parent.postMessage, leading to unauthorized MCP tool execution such as taking screenshots, reading page source, or any other registered capability. This issue has been fixed in version 1.85.10.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Appium
Appium appium-mcp
CPEs cpe:2.3:a:appium:appium-mcp:*:*:*:*:*:node.js:*:*
Vendors & Products Appium
Appium appium-mcp
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description MCP Appium is an MCP server that provides AI assistants with tools to automate mobile app testing on Android and iOS. In versions prior to 1.85.10, the createLocatorGeneratorUI function interpolates attacker-controlled element attributes — text, content-desc, resource-id, and locator selector values — directly into an HTML template literal without any HTML or JavaScript context escaping. An attacker who controls the UI of the app under test can inject arbitrary HTML and JavaScript into the MCP UI resource returned by the generate_locators tool. When a victim's MCP client renders this resource, the injected script executes and can invoke arbitrary MCP tools via window.parent.postMessage, leading to unauthorized MCP tool execution such as taking screenshots, reading page source, or any other registered capability. This issue has been fixed in version 1.85.10.
Title MCP Appium: Unescaped Locator Data XSS in MCP-UI Resource (createLocatorGeneratorUI)
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jul 14, 2026, 2:31 PM
Reserved
Jun 30, 2026, 8:21 PM
Status
Analyzed
Published
Jul 13, 2026, 10:16 PM
Modified
Oct 24, 2026, 10:10 PM