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 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Maxkb | Maxkb | < 2.8.0 |
Related Weaknesses (CWE)
References
- https://github.com/1Panel-dev/MaxKB/releases/tag/v2.8.0Release Notes
- https://github.com/1Panel-dev/MaxKB/security/advisories/GHSA-q2qg-43vq-f2wvVendor Advisory
FAQ
What is CVE-2026-39426?
CVE-2026-39426 is a vulnerability with a CVSS score of 5.4 (MEDIUM). 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 <ifr...
How severe is CVE-2026-39426?
CVE-2026-39426 has been rated MEDIUM with a CVSS base score of 5.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-39426?
Check the references section above for vendor advisories and patch information. Affected products include: Maxkb Maxkb.