How severe is CVE-2026-58500?

CVE-2026-58500 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity high, and availability none.

Is CVE-2026-58500 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-58500?

CVE-2026-58500 affects Appium Appium-mcp. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-58500?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-58500 published?

CVE-2026-58500 was published on 2026-07-13 and last updated on 2026-08-26.

CVE-2026-58500

CVE-2026-58500 is a high-severity vulnerability in Appium Appium-mcp with a CVSS 3.x base score of 8.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: High (CVSS 3.x base score 8.2)
EPSS exploit prediction: 0% (32nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Appium Appium-mcp
Published: 2026-07-13
Last modified: 2026-08-26

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.

Frequently asked questions

What is CVE-2026-58500?: 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.
How severe is CVE-2026-58500?: CVE-2026-58500 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity high, and availability none.
Is CVE-2026-58500 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-58500?: CVE-2026-58500 affects Appium Appium-mcp. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-58500?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-58500 published?: CVE-2026-58500 was published on 2026-07-13 and last updated on 2026-08-26.

References

Affected products (1)

cpe:2.3:a:appium:appium-mcp:*:*:*:*:*:node.js:*:*

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