1Panel-dev MaxKB up to 2.7.x cross site scripting

Summaryinfo

A vulnerability was found in 1Panel-dev MaxKB up to 2.7.x. It has been rated as problematic. The impacted element is an unknown function. The manipulation leads to cross site scripting. This vulnerability is uniquely identified as CVE-2026-39426. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in 1Panel-dev MaxKB up to 2.7.x and classified as problematic. This issue affects an unknown function. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. The summary by CVE is:

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 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 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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-39426 since 04/07/2026. The exploitation is known to be easy. The attack may be initiated remotely. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

Upgrading to version 2.8.0 eliminates this vulnerability. The upgrade is hosted for download at github.com.

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Productinfo

Vendor

• 1Panel-dev

Name

• MaxKB

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7

Website

• Product: https://github.com/1Panel-dev/MaxKB/

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