# CVE-2026-39423: Stored XSS via Eval Injection in EchartsRander Component

> Attackers can inject JavaScript into the AI chat interface, leading to stored XSS and potential account takeover in MaxKB.

- **Severity:** Medium 6.9 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 14 Apr 2026
- **Updated:** 14 Apr 2026
- **Also known as:** GHSA-462x-99gf-mp79

## What is CVE-2026-39423?

CVE-2026-39423 is a medium-severity cross-site scripting vulnerability in 1Panel-dev MaxKB, published on 14 Apr 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

MaxKB is an open-source AI assistant for enterprise. Versions 2.7.1 and below contain an Eval Injection vulnerability in the Markdown rendering engine that allows any user capable of interacting with the AI chat interface to execute arbitrary JavaScript in the browsers of other users, including administrators, resulting in Stored Cross-Site Scripting (XSS). This issue has been fixed in version 2.8.0.

Weakness: CWE-95 (Improper Neutralization of Directives in Dynamically Evaluated Code), CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-39423?

It affects 1 product.


Products: Maxkb Maxkb.

## How do I fix CVE-2026-39423?

No fix has been published for CVE-2026-39423 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-39423 being exploited?

There is no known exploitation of CVE-2026-39423 in the wild and no public exploit code.

## Other vulnerabilities in 1Panel-dev MaxKB

- [CVE-2025-66419](https://insights.sbomify.com/CVE-2025-66419/): MaxKB vulnerable to privilege escalation through sandbox bypass (high 8.8)
- [CVE-2025-66446](https://insights.sbomify.com/CVE-2025-66446/): MaxKB has a Python sandbox LD_PRELOAD bypass (high 8.8)
- [CVE-2025-64511](https://insights.sbomify.com/CVE-2025-64511/): MaxKB has SSRF in sandbox (high 7.4)
- [CVE-2026-39422](https://insights.sbomify.com/CVE-2026-39422/): MaxKB has Stored XSS via ChatHeadersMiddleware (medium 6.9)
- [CVE-2024-56137](https://insights.sbomify.com/CVE-2024-56137/): MaxKB RCE vulnerability in function library (medium 6.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-39423 and fix it if it is affected.

What it is: CVE-2026-39423 is a medium-severity cross-site scripting vulnerability in 1Panel-dev MaxKB, published on 14 Apr 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-39423 in the wild and no public exploit code.

Affected product: 1Panel-dev MaxKB. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-39423/ (Markdown: https://insights.sbomify.com/CVE-2026-39423/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-39423
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-39423
- OSV: https://osv.dev/vulnerability/CVE-2026-39423

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-39423/
Summaries are generated and may contain mistakes; the official description above is the record.