CVE-2026-5619: Braffolk mcp-summarization RCE Vulnerability

CVE-2026-5619 Overview

A command injection vulnerability has been identified in Braffolk mcp-summarization-functions up to version 0.1.5. The flaw exists within the summarize_command component, specifically in the file src/server/mcp-server.ts. An attacker with local access can manipulate the command argument to inject and execute arbitrary operating system commands on the affected system.

Critical Impact

Local attackers can exploit improper input validation in the summarize_command function to achieve OS command injection, potentially leading to unauthorized command execution, data exfiltration, or further system compromise.

Affected Products

• Braffolk mcp-summarization-functions versions up to and including 0.1.5

Discovery Timeline

• 2026-04-06 - CVE-2026-5619 published to NVD
• 2026-04-07 - Last updated in NVD database

Technical Details for CVE-2026-5619

Vulnerability Analysis

This vulnerability is classified as OS Command Injection (CWE-77: Improper Neutralization of Special Elements used in a Command). The flaw resides in the summarize_command function within src/server/mcp-server.ts, where user-controllable input is passed to a system command without proper sanitization or validation.

The vulnerability requires local access to exploit, meaning an attacker must already have some level of access to the system or application context where mcp-summarization-functions is running. The exploit has been publicly disclosed and may be actively used, though the vendor was contacted about this disclosure and did not respond.

Root Cause

The root cause stems from inadequate input validation and sanitization of the command argument passed to the summarize_command function. When user-supplied data is incorporated into system commands without proper escaping or validation, attackers can break out of the intended command context and execute arbitrary commands. This is a classic command injection pattern where shell metacharacters or command separators are not filtered from input before command execution.

Attack Vector

The attack requires local access to the affected system. An attacker with the ability to interact with the mcp-summarization-functions application can craft malicious input containing shell metacharacters (such as ;, |, &&, or backticks) that, when processed by the vulnerable summarize_command function, results in the execution of unintended operating system commands.

The vulnerability mechanism involves the improper handling of the command argument in the src/server/mcp-server.ts file. When a malicious payload is passed as input, the application fails to sanitize special characters, allowing command chaining or injection. For detailed technical analysis and proof-of-concept information, refer to the GitHub Issue Discussion and VulDB Vulnerability Entry.

Detection Methods for CVE-2026-5619

Indicators of Compromise

• Unexpected or anomalous process spawning from the mcp-summarization-functions application or Node.js processes
• Suspicious command-line arguments containing shell metacharacters (;, |, &&, ||, backticks) in application logs
• Unusual outbound network connections or data exfiltration attempts originating from application processes

Detection Strategies

• Monitor application logs for the summarize_command function being called with suspicious input patterns containing shell injection characters
• Implement runtime application self-protection (RASP) to detect command injection attempts in real-time
• Deploy endpoint detection solutions to identify unexpected child processes spawned from Node.js applications

Monitoring Recommendations

• Enable verbose logging for the mcp-summarization-functions application to capture all command invocations
• Set up alerts for process execution chains that show Node.js spawning system shells or unexpected binaries
• Monitor file system changes and network activity from processes associated with the vulnerable application

How to Mitigate CVE-2026-5619

Immediate Actions Required

• Identify all instances of Braffolk mcp-summarization-functions version 0.1.5 and earlier in your environment
• Restrict local access to systems running the vulnerable application to trusted users only
• Consider disabling or isolating the summarize_command functionality until a patch is available
• Implement network segmentation to limit potential lateral movement if exploitation occurs

Patch Information

As of the last update, the vendor has not responded to disclosure attempts, and no official patch is available. Organizations should monitor the Braffolk mcp-summarization-functions repository and VulDB for updates regarding security fixes.

Workarounds

• Implement application-level input validation to sanitize the command argument before processing, filtering shell metacharacters and command separators
• Use allowlisting to restrict the command argument to a predefined set of safe values
• Deploy a web application firewall (WAF) or input filtering layer to block requests containing command injection patterns
• Run the application in a sandboxed or containerized environment to limit the impact of successful exploitation

# Example input validation approach (conceptual)
# Implement strict allowlisting for command argument values
# Filter or escape: ; | & $ ` ( ) { } [ ] < > ! # ' " \
# Consider using parameterized command execution instead of shell invocation