CVE-2026-0756: GitHub Kanban MCP Server RCE Vulnerability

CVE-2026-0756 Overview

CVE-2026-0756 is a critical command injection vulnerability affecting github-kanban-mcp-server that allows remote attackers to execute arbitrary code on affected installations. This vulnerability does not require authentication to exploit, significantly increasing its risk profile and potential for widespread exploitation.

The specific flaw exists within the handling of the create_issue parameter. The issue results from the lack of proper validation of a user-supplied string before using it to execute a system call via the execAsync function. An attacker can leverage this vulnerability to execute code in the context of the service account, potentially leading to complete system compromise.

Critical Impact

Unauthenticated remote attackers can achieve arbitrary code execution on vulnerable github-kanban-mcp-server installations, potentially leading to complete system compromise, data exfiltration, and lateral movement within the network.

Affected Products

• github-kanban-mcp-server (all versions prior to patch)

Discovery Timeline

• 2026-01-23 - CVE-2026-0756 published to NVD
• 2026-01-26 - Last updated in NVD database

Technical Details for CVE-2026-0756

Vulnerability Analysis

This command injection vulnerability (CWE-78) represents a severe security flaw in the github-kanban-mcp-server application. The vulnerability stems from improper handling of user-supplied input in the create_issue parameter, which is passed directly to the execAsync function without adequate sanitization or validation.

When processing issue creation requests, the application constructs a system command that incorporates user-controlled data. Because there is no proper input validation or escaping mechanism in place, attackers can inject shell metacharacters and additional commands that will be executed by the underlying operating system.

The network-accessible nature of this vulnerability, combined with the lack of authentication requirements, means that any attacker with network access to the affected service can exploit this flaw. Successful exploitation results in code execution with the privileges of the service account running the github-kanban-mcp-server process.

Root Cause

The root cause of this vulnerability is the absence of proper input validation and sanitization before passing user-controlled data to system command execution functions. The create_issue parameter is directly incorporated into a shell command executed via execAsync, allowing shell metacharacters such as semicolons, pipes, and backticks to break out of the intended command context and inject malicious commands.

This is a classic example of CWE-78 (Improper Neutralization of Special Elements used in an OS Command), where the application fails to neutralize or incorrectly neutralizes special elements that could modify the intended OS command.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. An attacker can craft a malicious request to the github-kanban-mcp-server containing specially crafted input in the create_issue parameter. The malicious payload would include shell metacharacters followed by arbitrary commands.

For example, an attacker might submit a request where the create_issue parameter contains command injection payloads using characters like ;, |, $(...), or backticks to break out of the intended command context and execute arbitrary shell commands. The injected commands would then be executed by the execAsync function with the privileges of the service account.

For detailed technical analysis and exploitation specifics, refer to the Zero Day Initiative Advisory ZDI-26-022.

Detection Methods for CVE-2026-0756

Indicators of Compromise

• Unusual process spawning from the github-kanban-mcp-server service, particularly shells like /bin/sh, /bin/bash, or cmd.exe
• Unexpected outbound network connections originating from the service process
• Presence of web shells, reverse shells, or persistence mechanisms in writable directories
• Anomalous entries in application logs showing malformed create_issue requests containing shell metacharacters

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing shell metacharacters in API parameters
• Monitor process creation events for child processes spawned by the github-kanban-mcp-server service
• Deploy endpoint detection and response (EDR) solutions like SentinelOne to identify command injection attack patterns and suspicious process behavior
• Review application logs for requests with unusual characters such as ;, |, $(), or backticks in the create_issue parameter

Monitoring Recommendations

• Enable detailed logging for all incoming API requests to the github-kanban-mcp-server
• Configure alerting for any shell processes spawned as children of the application process
• Monitor for file system changes in application directories and common web shell locations
• Implement network monitoring to detect command-and-control communications or data exfiltration attempts

How to Mitigate CVE-2026-0756

Immediate Actions Required

• Restrict network access to github-kanban-mcp-server instances using firewall rules to allow only trusted sources
• Place the service behind a reverse proxy or WAF with input validation capabilities
• If not required for operations, consider temporarily disabling the service until a patch is applied
• Audit existing systems for signs of compromise using the indicators listed above

Patch Information

Monitor the github-kanban-mcp-server project and the Zero Day Initiative Advisory ZDI-26-022 for official patch releases. Apply vendor-supplied patches as soon as they become available. Ensure all instances of the vulnerable software are identified and updated in your environment.

Workarounds

• Implement strict input validation at the network perimeter using a WAF to filter requests containing shell metacharacters
• Deploy network segmentation to isolate github-kanban-mcp-server from critical systems
• Run the service with minimal privileges using a dedicated low-privilege service account
• Consider containerization to limit the blast radius of potential exploitation

Organizations should implement input validation at the application layer. A recommended approach involves sanitizing all user inputs before they reach command execution functions:

# Example: Network restriction using iptables
# Restrict access to the service port (adjust port as needed)
iptables -A INPUT -p tcp --dport 3000 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 3000 -j DROP