CVE-2025-66481 CRITICAL

CVE-2025-66481: DeepChat's Incomplete XSS Fix Allows RCE through Mermaid Content

Vendor Thinkinaixyz
Product deepchat
Weakness CWE-80 · XSS · basic
Published December 9, 2025
Last update December 9, 2025

CVSS base score

9.7/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction Required
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

What the vulnerability does

01Description

DeepChat is an open-source AI chat platform that supports cloud models and LLMs. Versions 0.5.1 and below are vulnerable to XSS attacks through improperly sanitized Mermaid content. The recent security patch for MermaidArtifact.vue is insufficient and can be bypassed using unquoted HTML attributes combined with HTML entity encoding. Remote Code Execution is possible on the victim's machine via the electron.ipcRenderer interface, bypassing the regex filter intended to strip dangerous attributes. There is no fix at time of publication.

Key dates

02Disclosure timeline

December 9, 2025 CVE published
December 9, 2025 Record updated