CVE-2026-39425— MaxKB: Stored XSS via Unsanitized html_rander Tags in Markdown Rendering
Quick assessment
Affected
1Panel-dev MaxKB
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
MaxKB是1Panel-dev开源的一款基于大语言模型和 RAG 的开源知识库问答系统。 MaxKB 2.7.1及之前版本存在安全漏洞，该漏洞源于应用开场白字段存在存储型跨站脚本，可能导致经过身份验证的用户注入任意HTML和JavaScript。
Possible ATT&CK Techniques 3 AI
T1059 · Command and Scripting Interpreter T1098 · Account Manipulation T1189 · Drive-by Compromise
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I. Basic Information for CVE-2026-39425
Vulnerability Information
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Vulnerability Title
MaxKB: Stored XSS via Unsanitized html_rander Tags in Markdown Rendering
Source: CVE Program / CVE List V5
Vulnerability Description
MaxKB is an open-source AI assistant for enterprise. Versions 2.7.1 and below contain a Stored Cross-Site Scripting (XSS) vulnerability that allows authenticated users to inject arbitrary HTML and JavaScript into the Application prologue (Opening Remarks) field by wrapping malicious payloads in <html_rander> tags. The backend fails to sanitize or encode HTML entities in the prologue field when applications are created or updated via the /admin/api/workspace/{workspace_id}/application endpoint, storing the raw payload directly in the database. The frontend then renders this content using an innerHTML-equivalent mechanism, trusting <html_rander>-wrapped content to be safe, which enables persistent DOM-based Stored XSS execution against any visitor who opens the affected chatbot interface. Exploitation can lead to session hijacking, unauthorized actions performed on behalf of victims (such as deleting workspaces or applications), and sensitive data exposure. This issue has been fixed in version 2.8.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
Web页面中脚本相关HTML标签转义处理不恰当(基本跨站脚本)
Source: CVE Program / CVE List V5
Vulnerability Title
MaxKB 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
MaxKB是1Panel-dev开源的一款基于大语言模型和 RAG 的开源知识库问答系统。 MaxKB 2.7.1及之前版本存在安全漏洞，该漏洞源于应用开场白字段存在存储型跨站脚本，可能导致经过身份验证的用户注入任意HTML和JavaScript。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| 1Panel-dev | MaxKB | < 2.8.0 | - |
|
II. Public POCs for CVE-2026-39425
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-39425 (1)
-
Release v2.8.0 · 1Panel-dev/MaxKB · GitHub x_refsource_MISC
Same Patch Batch · 1Panel-dev · 2026-04-14 · 10 CVEs total
| CVE-2026-39420 | 6.3 MEDIUM | MaxKB: Sandbox escape via LD_PRELOAD bypass |
| CVE-2026-39421 | 6.3 MEDIUM | MaxKB: Sandbox escape via ctypes and unhooked SYS_pkey_mprotect |
| CVE-2026-39418 | 5.0 MEDIUM | MaxKB: SSRF via sandbox network hook bypass |
| CVE-2026-39417 | 4.6 MEDIUM | MaxKB: RCE via MCP stdio command injection in workflow engine |
| CVE-2026-39419 | 3.1 LOW | MaxKB: Sandbox Result Validation Bypass via Tool Output Spoofing |
| CVE-2026-39424 | MaxKB has CSV Injection in its Application Chat Export Functionality | |
| CVE-2026-39423 | Stored XSS via Eval Injection in EchartsRander Component | |
| CVE-2026-39426 | MaxKB: Stored XSS via Unsanitized iframe_render Parsing | |
| CVE-2026-39422 | MaxKB has Stored XSS via ChatHeadersMiddleware |
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V. Comments for CVE-2026-39425
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