6.9

CVE-2026-39422: MaxKB has Stored XSS via ChatHeadersMiddleware

Analyzed
Published 14-04-2026Last modified 14-04-2026

Vulnerability summary

CVE-2026-39422 is a medium (CVSS 6.9) vulnerability in 1panel-dev maxkb. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 12.1% of scored vulnerabilities. 1 public exploit is recorded.

Priority
Routine

Not severe (CVSS 6.9, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
6.9/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.22%
0%100%
Low · -0.09 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1github

Timeline

  1. 14-04-2026
    PublishedVulnerability first disclosed.
  2. 14-04-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

0.22%

Chance of exploitation in the next 30 days

Percentile

12%

Versus all other CVEs

30-day change

Decrease -0.09 pp

From 0.30% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • githubUnverified

    Maxkb

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, low-privilege account, user interaction (CVSS vector). Other conditions: not stated in public data.

1panel-dev1 product
Maxkb1 product

2 vendors · 2 products

References

3 links