CVE-2025-66481

DeepChat's Incomplete XSS Fix Allows RCE through Mermaid Content

State: Published
Severity: 9.7 Critical
Published: Dec 9, 2025
Updated: Dec 9, 2025
Reserved: Dec 2, 2025

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	9.7 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H	GitHub_M

Weaknesses

CWE-80 Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-94 Improper Control of Generation of Code ('Code Injection')

Affected Products

Product	Versions
deepchatThinkInAIXYZ	<= 0.5.1Affected

References

https://github.com/ThinkInAIXYZ/deepchat/security/advisories/GHSA-h9f5-7hhf-fqm4

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