CVE-2025-66481 - CVE House
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Status published Critical CVE-2025-66481

DeepChat's Incomplete XSS Fix Allows RCE through Mermaid Content

Vulnerability 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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

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Affected Vendor

ThinkInAIXYZ

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Affected Software

deepchat
Vulnerable Versions:
<= 0.5.1

Timeline

Official Publish: December 9th, 2025
Last Modified: December 9th, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Weaknesses (CWE)

CWE-80 CWE-79 CWE-94

MITRE ATT&CK TTPs

T1189 Drive-by Compromise
Initial Access
T1059 Command and Scripting Interpreter
Execution
T1552 Unsecured Credentials
Credential Access
T1071 Application Layer Protocol
Command and Control
T1565 Data Manipulation
Impact
T1059.007 JavaScript
Execution
T1539 Steal Web Session Cookie
Collection
T1213 Data from Information Repositories
Collection
T1567 Exfiltration Over Web Service
Exfiltration
T1491.001 Defacement
Impact
T1190 Exploit Public-Facing Application
Initial Access
T1505.003 Web Shell
Persistence
T1105 Ingress Tool Transfer
Command and Control
T1565.002 Stored Data Manipulation
Impact