CVE-2026-31862: Cloud CLI RCE Vulnerability

CVE-2026-31862 Overview

CVE-2026-31862 is a command injection vulnerability affecting Cloud CLI (also known as Claude Code UI), a desktop and mobile user interface for Claude Code, Cursor CLI, Codex, and Gemini-CLI. Prior to version 1.24.0, multiple Git-related API endpoints utilize execAsync() with string interpolation of user-controlled parameters including file, branch, message, and commit values. This allows authenticated attackers to execute arbitrary operating system commands on the underlying host system.

Critical Impact

Authenticated attackers can achieve remote code execution by injecting malicious commands through Git-related API parameters, potentially leading to complete system compromise, data theft, or lateral movement within the network.

Affected Products

• Cloud CLI (Claude Code UI) versions prior to 1.24.0
• Desktop UI installations for Claude Code, Cursor CLI, Codex, and Gemini-CLI
• Mobile UI installations for Claude Code, Cursor CLI, Codex, and Gemini-CLI

Discovery Timeline

• 2026-03-11 - CVE-2026-31862 published to NVD
• 2026-03-12 - Last updated in NVD database

Technical Details for CVE-2026-31862

Vulnerability Analysis

This vulnerability is classified as CWE-78 (Improper Neutralization of Special Elements used in an OS Command), commonly known as OS Command Injection. The flaw exists in how Cloud CLI handles user-supplied input when constructing shell commands for Git operations.

The application's Git-related API endpoints accept user-controlled parameters such as file paths, branch names, commit messages, and commit identifiers. These parameters are directly interpolated into command strings passed to execAsync() without proper sanitization or parameterization. An authenticated attacker can exploit this by injecting shell metacharacters and commands within these parameters.

The network-based attack vector combined with the ability to break out of the application's scope makes this vulnerability particularly severe. Successful exploitation could result in complete host compromise, including unauthorized access to sensitive data, installation of malware, or using the compromised system as a pivot point for further attacks.

Root Cause

The root cause is the use of unsafe string interpolation when building shell commands. Instead of using parameterized command execution or proper input sanitization, the application directly concatenates user input into command strings. Common shell metacharacters such as backticks, semicolons, pipes, and command substitution syntax ($(...)) can be used to break out of the intended command context and execute arbitrary commands.

Attack Vector

The vulnerability is exploitable over the network by authenticated users. An attacker with valid credentials to the Cloud CLI application can submit specially crafted values through the Git-related API endpoints. When these malicious parameters are processed by the backend and passed to execAsync(), the injected commands execute with the privileges of the application process.

For example, a malicious branch name or commit message containing shell metacharacters would be interpreted by the shell rather than treated as literal string data. The vulnerability affects multiple API endpoints that handle Git operations, increasing the attack surface available to authenticated users.

Technical details and proof-of-concept information can be found in the GitHub Security Advisory GHSA-f2fc-vc88-6w7q.

Detection Methods for CVE-2026-31862

Indicators of Compromise

• Unusual shell command execution patterns originating from the Cloud CLI application process
• Git API requests containing shell metacharacters such as ;, |, $(), or backticks in parameter values
• Unexpected child processes spawned by the Cloud CLI service
• Log entries showing malformed Git commands or shell syntax errors

Detection Strategies

• Monitor API request logs for Git-related endpoints containing suspicious characters or command injection patterns
• Implement application-level logging to capture all parameters passed to execAsync() calls
• Deploy endpoint detection and response (EDR) solutions to identify anomalous process execution chains
• Configure web application firewalls (WAF) to detect and block common command injection payloads

Monitoring Recommendations

• Enable detailed audit logging for the Cloud CLI application and its API endpoints
• Monitor process creation events on systems running Cloud CLI, particularly child processes of the main application
• Implement alerting for any Git operations with unusual parameter lengths or character patterns
• Review network traffic for API calls to Git-related endpoints with encoded or obfuscated payloads

How to Mitigate CVE-2026-31862

Immediate Actions Required

• Upgrade Cloud CLI (Claude Code UI) to version 1.24.0 or later immediately
• Audit access logs for any suspicious Git API activity prior to patching
• Review user accounts with access to the application and remove unnecessary privileges
• Implement network segmentation to limit the blast radius if exploitation has occurred

Patch Information

The vulnerability has been fixed in Cloud CLI version 1.24.0. Users should upgrade to this version or later to remediate the issue. The fix is available through the GitHub Release v1.24.0.

The security advisory with full details is available at the GitHub Security Advisory GHSA-f2fc-vc88-6w7q.

Workarounds

• Restrict network access to the Cloud CLI application to trusted IP addresses only
• Implement additional authentication layers such as VPN or zero-trust network access before the application
• Disable or limit access to Git-related API endpoints if they are not required for operations
• Deploy a reverse proxy with strict input validation rules to filter malicious requests before they reach the application

# Example: Restrict access to Cloud CLI using iptables
iptables -A INPUT -p tcp --dport 8080 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8080 -j DROP