Impact Analysis

If you are a developer using Tophat on macOS versions prior to 2.5.1, this vulnerability allows an attacker to execute arbitrary commands on your workstation.

Since the attacker commands run with your user permissions and no confirmation dialog is shown for trusted build hosts, an attacker could silently compromise your system.

This could lead to unauthorized access, data theft, or further compromise of your development environment.

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Executive Summary

CVE-2026-39862 is a command injection vulnerability in the Tophat mobile applications testing harness affecting versions prior to 2.5.1.

The vulnerability occurs when a developer accesses a specially crafted URL using the tophat:// scheme or http://localhost:29070, where the "arguments" query parameter is not properly sanitized.

This unsanitized input is passed directly to a shell command executed via `/bin/bash -c`, allowing an attacker to execute arbitrary commands on the developer's macOS workstation with the same user permissions.

No confirmation dialog appears for previously trusted build hosts, increasing the risk of silent exploitation.

The vulnerability has been fixed in version 2.5.1 by sanitizing all command line arguments and validating allowed characters.

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Detection Guidance

This vulnerability can be detected by inspecting any usage of tophat:// or http://localhost:29070 URLs that include the "arguments" query parameter, which is parsed unsanitized and passed to a shell command. Monitoring for suspicious or unexpected commands executed via /bin/bash -c on a developer's macOS workstation may indicate exploitation attempts.

As a practical detection step, you can manually review URLs used with Tophat to ensure they do not contain malicious arguments. Additionally, monitoring logs in development tools such as Xcode for unusual shell command executions or errors related to app launching with shell metacharacters can help identify attempts to exploit this vulnerability.

Specific commands are not provided in the resources, but general approaches include:

• Checking shell command history for suspicious /bin/bash -c executions triggered by Tophat.
• Using network monitoring tools to detect access to tophat:// URLs or HTTP requests to localhost:29070 with suspicious query parameters.
• Reviewing Xcode logs for errors or warnings related to app launch arguments containing shell metacharacters.

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Mitigation Strategies

The primary immediate step to mitigate this vulnerability is to update Tophat to version 2.5.1 or later, where the vulnerability has been fixed.

As a temporary workaround before updating, users should manually inspect all Tophat URLs before clicking to ensure they do not contain malicious arguments that could lead to command injection.

The fix involves sanitizing all command line arguments and validating them against an allowlist of permitted characters to prevent shell metacharacter injection.

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Compliance Impact

The provided information does not specify any direct impact of this vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.

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