CVE-2025-66222 DeepChat Cross-Site Scripting(XSS) escalate to Remote Code Execution(RCE)

Critical 9.7 Published 3 Dec 2025 Updated 3 Dec 2025

Stored XSS in DeepChat's Mermaid renderer allows attackers to execute arbitrary code via Electron IPC bridge escalation.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2025-66222?

CVE-2025-66222 is a critical cross-site scripting vulnerability in ThinkInAIXYZ deepchat, published on 3 Dec 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

DeepChat is a smart assistant uses artificial intelligence. In 0.5.0 and earlier, there is a Stored Cross-Site Scripting (XSS) vulnerability in the Mermaid diagram renderer allows an attacker to execute arbitrary JavaScript within the application context. By leveraging the exposed Electron IPC bridge, this XSS can be escalated to Remote Code Execution (RCE) by registering and starting a malicious MCP (Model Context Protocol) server.

Weakness: CWE-79, CWE-94

Which versions are affected by CVE-2025-66222?

It affects 1 product.

Products include Thinkinai Deepchat.

How do I fix CVE-2025-66222?

No fix has been published for CVE-2025-66222 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2025-66222 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-66222 exists.

Sources

Also known as GHSA-v8v5-c872-mf8r.