CVE Catalog

CVE-2026-39426

MediumCVSS 5.4
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.19%

9th percentile - higher than 9% of all known CVEs

Summary

MaxKB versions 2.7.1 and below contain a Stored XSS vulnerability where the frontend's MdRenderer.vue component parses custom <iframe_render> tags from LLM responses or Application Prologue configurations, bypassing Markdown sanitization and XSS filtering. The unsanitized HTML is passed to IframeRender.vue and rendered into an iframe via srcdoc with sandbox="allow-scripts allow-same-origin", allowing injected scripts to escape the iframe and execute JavaScript in the parent window.

Risk Assessment

This high-impact Stored XSS can lead to session hijacking, unauthorized actions, and sensitive data exposure, as the Prologue is rendered for any user visiting the application's chat interface.

Recommendation

Update MaxKB to version 2.8.0 or later, which fixes this issue. Until patched, consider restricting Prologue configuration capabilities and monitoring for suspicious activity.

Other vulnerabilities in MaxKB

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS