CVE-2025-66481
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-12-09

Last updated on: 2025-12-11

Assigner: GitHub, Inc.

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.
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Meta Information
Published
2025-12-09
Last Modified
2025-12-11
Generated
2026-06-16
AI Q&A
2025-12-09
EPSS Evaluated
2026-06-14
NVD
CVE-2025-66481
EUVD
EUVD-2025-201843
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
thinkinaixyz deepchat 0.5.1
thinkinai deepchat to 0.5.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CWE-94 The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
CWE-80 The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as "<", ">", and "&" that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages.
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Executive Summary

This vulnerability affects DeepChat versions 0.5.1 and below, where improperly sanitized Mermaid content allows Cross-Site Scripting (XSS) attacks. The recent patch for MermaidArtifact.vue is insufficient and can be bypassed using unquoted HTML attributes combined with HTML entity encoding. This enables Remote Code Execution on the victim's machine via the electron.ipcRenderer interface by bypassing the regex filter meant to block dangerous attributes. There is currently no fix available.

Impact Analysis

The vulnerability can lead to Remote Code Execution on the victim's machine, allowing attackers to execute arbitrary code remotely. This can result in full compromise of the affected system, including data theft, system manipulation, or further attacks within the network.

Mitigation Strategies

Since there is no fix available at the time of publication, immediate steps include avoiding use of DeepChat versions 0.5.1 and below, especially in environments where untrusted Mermaid content is processed. Additionally, restrict or monitor usage of the electron.ipcRenderer interface to limit potential remote code execution. Applying strict input validation and sanitization on Mermaid content before rendering may help mitigate risk until an official patch is released.

Detection Guidance

This vulnerability can be detected by scanning for Mermaid content in DeepChat versions 0.5.1 and below that contain unquoted HTML attributes with event handlers such as 'onerror' combined with HTML entity encoding. Since the sanitization regex only detects quoted attributes, look for patterns like onerror=alert(1) or similar unquoted event handlers in Mermaid content. You can search for suspicious Mermaid content or payloads in logs or stored data. For example, using grep or similar tools to find unquoted event handlers in Mermaid files or data: grep -P 'on\w+\s*=\s*[^"\'\s]+' *.md or *.vue files. Additionally, monitor for Electron ipcRenderer calls triggered by such payloads. Since there is no fix yet, detection relies on identifying these malicious patterns in input or stored Mermaid content. [1]

Compliance Impact

The provided resources do not contain information regarding the impact of this vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.

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