CVE-2026-39422CWE-79

MaxKB has Stored XSS via ChatHeadersMiddleware

Medium · published April 14, 2026

CVSS v4.0
6.9
EPSS
0%
Percentile
22.1
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
6.9 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
EPSS
0.00305 · 22.1th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-04-14T00:22Z
EPSS history
Timeline
  • 14 APR 00:22Z
    MaxKB has Stored XSS via ChatHeadersMiddleware
    cvelistv5