# CVE-2026-48527: HAX CMS stored XSS via sanitizer bypass in saveNode endpoint

Source: https://junglewise.ai/threats/cve-2026-48527-hax-cms-stored-xss-via-sanitizer-bypass-in-savenode-endpoint  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-29. Updated: 2026-05-29  
License: CC BY 4.0 with a link back

CVE-2026-48527 · Severity: high · CVSS 8.7 · Published 2026-05-29

HaxCMS, a content management system, is vulnerable to a security flaw that allows users with page-editing permissions to inject malicious scripts into website pages. If another user, such as an administrator, views the affected page and interacts with the injected content, the attacker could steal sensitive session data or perform unauthorized actions on their behalf. This could lead to a full takeover of the site or unauthorized access to private data.

Technologies: [@haxtheweb/haxcms-nodejs (npm)](https://junglewise.ai/threats/technologies/haxtheweb-haxcms-nodejs). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-48527 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-48527 being exploited in the wild.

**How severe is CVE-2026-48527?** High severity, with a CVSS score of 8.7, published 29 May 2026.

**Which products and versions are affected?** @haxtheweb/haxcms-nodejs (npm) <= 26.0.0, SEMVER:introduced=0,fixed=26.0.1.

**Is there a fix for CVE-2026-48527?** Yes. @haxtheweb/haxcms-nodejs (npm): upgrade to 26.0.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-48527 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-48527?** Check whether you run @haxtheweb/haxcms-nodejs (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- @haxtheweb/haxcms-nodejs (npm): upgrade to 26.0.1 or later

  ```sh
  npm install @haxtheweb/haxcms-nodejs@26.0.1
  ```


## Technical details

A stored Cross-Site Scripting (XSS) vulnerability exists in HaxCMS versions up to 26.0.0 within the `/system/api/saveNode` endpoint. The vulnerability is caused by a flaw in the regex-based HTML sanitizer, which fails to identify and strip event handler attributes (like 'onclick') if they are not preceded by whitespace (e.g., `href="#"onclick="..."`). An authenticated attacker with page-editing privileges can submit a crafted `node.body` parameter to inject malicious JavaScript. When a victim interacts with the injected element, the script executes in their browser context, potentially exposing JWTs in localStorage or application settings. The issue is addressed in version 26.0.1.

## Affected products

- HaxTheWeb @haxtheweb/haxcms-nodejs <= 26.0.0

## Identifiers

- CVE-2026-48527
- GHSA-g2g8-95qg-v35h

## Timeline

- 2026-05-21: disclosed: Vulnerability reported to vendor
- 2026-05-29: advisory: GitHub Advisory published
- 2026-05-29: patched: Version 26.0.1 released

## References

- [https://api.github.com/users/kn1ph](https://api.github.com/users/kn1ph)
- [https://github.com/kn1ph](https://github.com/kn1ph)
- [https://api.github.com/users/kn1ph/gists%7B/gist_id%7D](https://api.github.com/users/kn1ph/gists%7B/gist_id%7D)
- [https://api.github.com/users/kn1ph/repos](https://api.github.com/users/kn1ph/repos)
- [https://avatars.githubusercontent.com/u/211062702?v=4](https://avatars.githubusercontent.com/u/211062702?v=4)
- [https://api.github.com/users/kn1ph/events%7B/privacy%7D](https://api.github.com/users/kn1ph/events%7B/privacy%7D)

## Related threats

- [haxtheweb HAX CMS denial of service in createSite endpoint](https://junglewise.ai/threats/cve-2026-46357-haxtheweb-hax-cms-denial-of-service-in-createsite-endpoint)
- [HAX CMS account takeover via Stored XSS and token exposure](https://junglewise.ai/threats/cve-2026-46511-hax-cms-account-takeover-via-stored-xss-and-token-exposure)
- [haxtheweb HAX CMS stored XSS in video-player component](https://junglewise.ai/threats/cve-2026-46496-haxtheweb-hax-cms-stored-xss-in-video-player-component)
- [HAX CMS stored XSS in iframe elements](https://junglewise.ai/threats/cve-2026-46396-hax-cms-stored-xss-in-iframe-elements)
- [HAX CMS private key disclosure and JWT forgery in Node.js backend](https://junglewise.ai/threats/cve-2026-46395-hax-cms-private-key-disclosure-and-jwt-forgery-in-node-js-backend)