CVE-2025-66562
Published: 05 December 2025
Description
TUUI is a desktop MCP client designed as a tool unitary utility integration. Prior to 1.3.4, a critical Remote Code Execution (RCE) vulnerability exists in Tuui due to an unsafe Cross-Site Scripting (XSS) flaw in the Markdown rendering component. Tuui…
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allows the execution of arbitrary JavaScript within ECharts code blocks. Combined with an exposed IPC interface that allows spawning processes, an attacker can execute arbitrary system commands on the victim's machine simply by having them view a malicious Markdown message. This vulnerability is fixed in 1.3.4.
Mitigating Controls (NIST 800-53 r5)AI
Directly mitigates the CVE by requiring timely flaw remediation through updating TUUI to version 1.3.4 or later, which fixes the unsafe XSS in the Markdown rendering component.
Prevents exploitation by validating untrusted Markdown inputs to block malicious JavaScript injection into ECharts code blocks.
Mitigates XSS by filtering the output of the Markdown rendering process to prevent execution of arbitrary JavaScript.
Security SummaryAI
CVE-2025-66562 is a critical remote code execution (RCE) vulnerability affecting TUUI, a desktop MCP client designed as a tool for unitary utility integration, in versions prior to 1.3.4. The flaw stems from an unsafe cross-site scripting (XSS) issue in the Markdown rendering component (CWE-79), which permits the execution of arbitrary JavaScript within ECharts code blocks (CWE-94). This vulnerability has a CVSS v3.1 base score of 9.6 (AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H), highlighting its high severity due to network accessibility, low attack complexity, and comprehensive impact on confidentiality, integrity, and availability.
A remote attacker can exploit this vulnerability by crafting a malicious Markdown message containing JavaScript in an ECharts code block. When a victim views the message in TUUI, the JavaScript executes in the application's context and leverages an exposed IPC interface capable of spawning processes, enabling the attacker to run arbitrary system commands on the victim's machine. No authentication or privileges are required, though user interaction is necessary to view the malicious content.
The vulnerability is addressed in TUUI version 1.3.4, as detailed in the project's GitHub security advisory (GHSA-qjhq-rgmr-6c3g), release notes, and the fixing commit. Security practitioners should advise users to update to v1.3.4 or later to mitigate the risk.
Details
- CWE(s)
Affected Products
AI Security AnalysisAI
- AI Category
- AI Agent Protocols and Integrations
- Risk Domain
- N/A
- OWASP Top 10 for LLMs 2025
- None mapped
- MITRE ATLAS Techniques
- None mapped
- Classification Reason
- No AI-related keywords detected.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The vulnerability is a client-side RCE via XSS in a desktop application's Markdown renderer, enabling arbitrary command execution through JavaScript and exposed IPC, directly facilitating T1203 Exploitation for Client Execution.