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CVE-2026-39426

MaxKB: Stored XSS via Unsanitized iframe_render Parsing

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 2.8.0
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

MaxKB is an open-source AI assistant for enterprise. Versions 2.7.1 and below contain a Stored Cross-Site Scripting (XSS) vulnerability where the frontend's MdRenderer.vue component parses custom <iframe_render> tags from LLM responses or Application Prologue configurations, bypassing standard Markdown sanitization and XSS filtering. The unsanitized HTML content is passed to the IframeRender.vue component, which renders it directly into an <iframe> via the srcdoc attribute configured with sandbox="allow-scripts allow-same-origin". This can be a dangerous combination, allowing injected scripts to escape the iframe and execute JavaScript in the parent window using window.parent. Since the Prologue is rendered for any user visiting an application's chat interface, this results in a high-impact Stored XSS that can lead to session hijacking, unauthorized actions, and sensitive data exposure. This issue has been fixed in version 2.8.0.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • 1Panel-dev MaxKB

    fixed in 2.8.0

References 2

GitHub · 1Panel-dev/MaxKB