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TI-2025-40905 Aliases CVE-2025-66481

DeepChat's Incomplete XSS Fix Allows RCE through Mermaid Content

Priority HIGH 76CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting, Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79 and CWE-94.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0058 47th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ThinkInAIXYZdeepchatup to 0.5.1—No fix listedCNA
  • deepchat VendorThinkInAIXYZ Affected up to 0.5.1 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:thinkinai:deepchat:*:*:*:*:*:*:*:*up to 0.5.1VulnerableThinkInAIXYZ
  • cpe:2.3:a:thinkinai:deepchat:*:*:*:*:*:*:*:* Versions up to 0.5.1 Vulnerable ·ThinkInAIXYZ

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-66481

References

Exploit 1

  • TI-2025-41440 Mermaid XSS vulnerability leads to Remote Code Execution CVSS 3.1CRITICAL 9.7
  • TI-2025-40724 DeepChat Cross-Site Scripting(XSS) escalate to Remote Code Execution(RCE) CVSS 3.1CRITICAL 9.7
  • TI-2025-35154 DeepChat One-click Remote Code Execution through Custom URL Handling CVSS 3.1CRITICAL 9.7
  • TI-2025-36426 DeepChat's Mermaid rendering has XSS leading to RCE CVSS 3.1CRITICAL 9.7

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences