MaxKB AI Assistant: Stored XSS in Versions 2.7.1 and Below

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5.1

MaxKB AI Assistant: Stored XSS in Versions 2.7.1 and Below

CVE-2026-39426

Summary

Older versions of MaxKB contain a security flaw that allows attackers to inject malicious code into the system, potentially allowing them to access sensitive information and take unauthorized actions. This issue has been fixed in version 2.8.0. Users are advised to update to the latest version to protect their system.

Original title

Original description

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.

nvd CVSS4.0 5.1

Vulnerability type

CWE-79 Cross-site Scripting (XSS)

Published: 14 Apr 2026 · Updated: 16 Apr 2026 · First seen: 14 Apr 2026