Quick overview

CVE ID: CVE-2025-68669
Vulnerability name: 5ire Markdown / Mermaid Remote Code Execution
Severity: Critical
CVSS score: 9.6
Risk level: Very high
Exploitability: High
Privileges required: None
User interaction: Required (user must view content)
Exploit availability: Proof-of-concept details are publicly available
Affected product: 5ire desktop AI assistant
Affected versions: Versions prior to the fixed release
Patched version: v0.15.2

What this issue is, in simple terms

This vulnerability allows an attacker to run commands on a user’s computer by getting them to open or view a specially crafted Markdown file inside the 5ire application.

5ire supports Mermaid diagrams, which are text-based diagrams rendered visually. Due to an insecure configuration in how these diagrams are handled, it is possible to embed hidden HTML and JavaScript directly inside a diagram. When the diagram is rendered, that hidden code executes automatically.

Because 5ire is a desktop application built on web technologies, the executing code is not limited to a browser sandbox. Instead, it can interact with internal application features and trigger system-level actions. This turns what might otherwise be a display issue into a full remote code execution vulnerability.

In practical terms, simply viewing a malicious diagram can be enough for an attacker to execute commands on the user’s machine.

How an attack typically works

1. Creation of malicious content
   An attacker crafts a Mermaid diagram that includes hidden HTML and JavaScript inside diagram labels. This code is not obvious to users reading the Markdown.
2. Delivery to the victim
   The malicious content may be delivered through:
   • A shared Markdown file
   • A copied Mermaid diagram
   • A README file in a repository
   • Any document rendered by 5ire that supports Markdown
3. User views the content
   The user only needs to open or preview the content in 5ire. No clicking or confirmation is required.
4. Automatic execution
   When the diagram is rendered, the embedded JavaScript runs inside the application’s renderer.
5. Command execution
   The malicious script uses exposed application APIs to register and trigger system commands, giving the attacker the ability to execute arbitrary code.

Technical proof-of-concept (high level — do not run)

Advisory PoC (conceptual):

graph TD
A["<img src=x onerror=electron.mcp.addServer({key:'test',command:'calc',args:[]});electron.mcp.activate({key:'test'})>"]

This single Mermaid node contains an <img> tag whose onerror handler executes JavaScript. The script first registers a server command using electron.mcp.addServer(...) and then immediately triggers it using electron.mcp.activate(...).

The end result is a system command being executed by the application.

This example demonstrates why allowing arbitrary HTML execution inside diagrams is extremely dangerous. This is not just a simple scripting issue in a rendered document — it directly bridges into native functionality provided by the desktop application.

Why this is worse than a normal browser XSS issue

In a typical website, cross-site scripting might allow an attacker to steal cookies or perform actions within the context of that site.

In this case, the application is a desktop app built on Electron. The injected script runs inside the application renderer and has access to native APIs exposed by the app. This allows the attacker to move from “running JavaScript” to “running operating system commands.”

That escalation makes the impact far more serious than standard browser-based XSS and qualifies this issue as full remote code execution on the host.

Potential impact

If exploited, an attacker could:

• Execute arbitrary commands on the affected system
• Install malware or persistent backdoors
• Steal sensitive data and credentials
• Monitor user activity
• Use the compromised system to move laterally within an environment

The attack does not require elevated privileges and does not rely on complex exploitation techniques.

Complete mitigation & remediation checklist (what to do now)

If you run 5ire, do this immediately

Patch immediately
Upgrade to the vendor’s fixed release (v0.15.2 or later). This is the most important and effective mitigation step.

Until you can patch

• Do not open Markdown files, repository READMEs, or shared documentation from unknown or untrusted sources inside 5ire
• Disable automatic Markdown preview or Mermaid rendering if the application provides that option

Isolate the application

• Run 5ire on systems that do not contain sensitive data
• For enterprise environments, temporarily block the application from running on critical hosts
• Use endpoint security controls to restrict what the application is allowed to execute

Harden renderer and API exposure (for developers or maintainers)

• Configure markdown-it-mermaid to use a strict security level and disallow HTML inside diagram nodes
• Remove or heavily restrict privileged APIs exposed through Electron’s contextBridge
• Require secure IPC validation for any renderer-to-main-process requests
• Sanitize all user-supplied content before rendering and avoid unsafe functions like innerHTML

Monitoring and detection guidance

• Look for suspicious creation or activation of MCP servers within application logs or configuration files
• Monitor for unusual process launches originating from the 5ire application
• Watch for unexpected outbound network connections shortly after Markdown content is opened
• Pay close attention to renderer console errors referencing electron.mcp calls

Detection & indicators of compromise (IoCs)

• Application version: Running any version earlier than the patched release is an indicator of exposure
• Configuration changes: Unexpected MCP server entries or command registrations
• Process behavior: Sudden execution of uncommon programs after viewing Markdown content
• User reports: Unexpected pop-ups, application crashes, or unexplained system behavior

Post-compromise response steps

If exploitation is suspected:

1. Immediately isolate the affected system from the network
2. Preserve logs, memory, and the rendered Markdown file for analysis
3. Assume local credentials may be compromised and rotate them
4. Rebuild the system from a trusted image if compromise is confirmed
5. Apply the patch before reconnecting the system

Final takeaway & official patch link

This vulnerability presents a realistic and high-impact attack path due to unsafe content rendering combined with exposed application APIs. Prompt patching fully mitigates the issue and should be treated as a priority.

Official vendor advisory and patch:
https://github.com/nanbingxyz/5ire/security/advisories/GHSA-5hpf-p8fw-j349