# CVE-2026-39426: MaxKB is an open-source AI assistant for enterprise. Versions 2.7.1 and below contain a Stored Cross-Site Scripting…

Source: https://junglewise.ai/threats/cve-2026-39426-maxkb-is-an-open-source-ai-assistant-for-enterprise-versions-2-7  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-14  
License: CC BY 4.0 with a link back

CVE-2026-39426 · Severity: medium · CVSS 5.4 · Published 2026-04-14

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.

Technologies: [Maxkb](https://junglewise.ai/threats/technologies/maxkb-maxkb). Vendors: [Maxkb](https://junglewise.ai/threats/vendors/maxkb).

## Quick answers

**Is CVE-2026-39426 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-39426 being exploited in the wild.

**How severe is CVE-2026-39426?** Medium severity, with a CVSS score of 5.4, published 14 April 2026.

**Which products and versions are affected?** Maxkb. The advisory does not name versions.

**Is there a fix for CVE-2026-39426?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected by CVE-2026-39426?** Check whether you run Maxkb. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Maxkb

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