CVE-2025-68669: 
Homebrew vulnerability analysis and mitigation

CVE-2025-68669 is a Remote Code Execution (RCE) vulnerability in 5ire, a cross-platform desktop AI assistant and Model Context Protocol (MCP) client. The flaw exists in versions up to and including v0.14.1 (the advisory notes affected versions as ≤v0.14.1, with v0.15.2 being the patched release). It was disclosed on December 23, 2025, via a GitHub Security Advisory. The vulnerability carries a CVSS v3.1 base score of 9.6 (Critical) (GitHub Advisory, Feedly).

The root cause is an insecure configuration in useMarkdown.ts, where the markdown-it-mermaid plugin is initialized with securityLevel: 'loose', explicitly permitting HTML tag rendering within Mermaid diagram nodes (CWE-79: Cross-Site Scripting). When a malicious Mermaid diagram containing an HTML tag (e.g., <img>) with an onerror event handler is rendered, arbitrary JavaScript executes in the Electron renderer process. Critically, the application exposes a privileged electron.mcp API object to the renderer via Electron's contextBridge, providing methods such as electron.mcp.addServer and electron.mcp.activate that can register and execute arbitrary system commands. The PoC payload is: ` ```mermaid graph TD A["<img src=x onerror=...>"]

``` ` (GitHub Advisory, Vulnerable Code).

Successful exploitation results in full remote code execution on the victim's host system with the privileges of the user running 5ire, enabling complete system compromise. An attacker can steal sensitive data, execute arbitrary commands, install malware, or pivot laterally within the network. All three security pillars — confidentiality, integrity, and availability — are rated High in the CVSS scoring, reflecting the severity of the potential damage (GitHub Advisory, Feedly).

A proof-of-concept exploit is publicly available in the GitHub Security Advisory, demonstrating the attack via a crafted Mermaid diagram. There is no confirmed evidence of in-the-wild exploitation at this time, and no threat actor attribution has been reported. The EPSS score is approximately 0.039% (0.000390), indicating a currently low probability of exploitation in the wild. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog (GitHub Advisory, Feedly).

1. Craft malicious Mermaid payload: Create a markdown document containing a Mermaid diagram with an embedded HTML tag and JavaScript payload, for example:

```mermaid
graph TD
A["<img src=x onerror=\"electron.mcp.addServer({name:'pwn',command:'calc'});electron.mcp.activate('pwn');\">"]  

2. **Deliver the payload**: Send the malicious markdown document to the target user via chat, email, shared file, or any channel where the victim would open it in 5ire (e.g., as an AI response or imported document).
3. **Trigger rendering**: When the victim opens or views the document in 5ire (version ≤0.14.1), the Markdown renderer processes the Mermaid block with `securityLevel: 'loose'`, injecting the `<img>` tag into the DOM.
4. **Execute JavaScript**: The `onerror` event fires when the image fails to load, executing the attacker-controlled JavaScript in the Electron renderer process.
5. **Abuse privileged MCP API**: The injected script calls `electron.mcp.addServer()` to register a malicious MCP server configuration with an arbitrary system command, then calls `electron.mcp.activate()` to execute that command on the host OS with the user's privileges.
6. **Achieve full RCE**: The attacker's command runs on the victim's system, enabling reverse shell establishment, data exfiltration, or further lateral movement ([GitHub Advisory](https://github.com/nanbingxyz/5ire/security/advisories/GHSA-5hpf-p8fw-j349)).

• File System: Unexpected new MCP server configuration entries added to 5ire's configuration files; presence of unknown scripts or executables in user-writable directories created around the time of 5ire usage.
• Process: Unusual child processes spawned by the 5ire Electron process (e.g., calc.exe, cmd.exe, bash, curl, powershell) that are not typical for normal application operation.
• Logs: Application logs showing Mermaid rendering errors or unexpected onerror JavaScript execution traces; Electron renderer process logs indicating calls to electron.mcp.addServer or electron.mcp.activate with unfamiliar server names or commands.
• Network: Unexpected outbound network connections from the 5ire process to unknown external IP addresses or domains, particularly following the opening of a markdown document (GitHub Advisory).

The vulnerability is patched in 5ire version 0.15.2, which changes the markdown-it-mermaid plugin configuration from securityLevel: 'loose' to securityLevel: 'strict', preventing HTML injection in Mermaid diagram nodes (5ire Release v0.15.2, Patch Commit). Users should upgrade to v0.15.2 or later immediately. As a temporary workaround prior to patching, avoid opening markdown or Mermaid diagram files from untrusted sources, and restrict 5ire usage to trusted documents only (GitHub Advisory).

The vulnerability was reported by security researcher c2an1 and disclosed via GitHub's security advisory program on December 23, 2025. The Hacker Wire covered the disclosure with an article titled "Critical RCE Discovered in 5ire AI Assistant — Unpatched Vulnerability Exposes Systems," highlighting the severity of the issue for users of the AI desktop client (The Hacker Wire). Social media posts on Mastodon and Bluesky from security-focused accounts amplified awareness of the CVE shortly after disclosure. CISA included the vulnerability in its weekly bulletin for the week of December 22, 2025 (CISA Bulletin).