Vulnerability · Published Dec 9, 2025 · Assigned by GitHub_M

CVE-2025-66481DeepChat's Incomplete XSS Fix Allows RCE through Mermaid Content

Critical 9.7

In plain English

A critical-severity cross-site scripting in deepchat from ThinkInAIXYZ. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities).

Severity (CVSS 3.1)9.7Critical

Exploit odds (30 days)0.6%top 52.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
ThinkInAIXYZ	deepchat	<= 0.5.1

Weakness: CWE-80, CWE-79, CWE-94 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

References

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