XSS in 1panel-Dev Maxkb

CVE-2026-39422

MaxKB is an open-source AI assistant for enterprise. Versions 2.7.1 and below contain a Stored Cross-Site Scripting (XSS) vulnerability through the application name or icon fields when creating an application. When a victim visits the public chat interface (/ui/chat/{access_token}), the ChatHeadersMiddleware retrieves the application data and directly inserts the unescaped application name and icon into the HTML response via string replacement. This allows an attacker to execute arbitrary JavaScript in the victim's browser context. This issue has been fixed in version 2.8.0.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.002 (12.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-39422?
CVE-2026-39422 is a medium-severity vulnerability in 1panel-Dev Maxkb, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-04-14.
How severe is CVE-2026-39422?
Medium severity. CVSS v3 base score is 5.4 out of 10.