# CVE-2026-19698: GutenKit plugin stored CSS injection

Source: https://junglewise.ai/threats/cve-2026-19698-gutenkit-plugin-stored-css-injection  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-02. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-19698 · Severity: low · CVSS 3.5 · Published 2026-09-02

GutenKit is a WordPress plugin that provides block-based content editing for the Gutenberg editor. The plugin fails to properly validate or escape CSS style settings, allowing users with Contributor role and above to inject arbitrary CSS into pages. This enables defacement and interface manipulation visible to other users and site visitors.

## Quick answers

**Is CVE-2026-19698 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-19698 being exploited in the wild.

**How severe is CVE-2026-19698?** Low severity, with a CVSS score of 3.5, published 2 September 2026.

**Which products and versions are affected?** GutenKit GutenKit before 2.5.1.

**Is there a fix for CVE-2026-19698?** A patch was published on 2026-09-01: version 2.5.1 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-19698 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-19698?** Check whether anything you run is named in the advisory. 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.

## Technical details

The vulnerability is a stored CSS injection in the GutenKit WordPress plugin (plugin slug: gutenkit-blocks-addon). The plugin accepts style settings via post meta fields (postBodyCss) and block attributes (blocksCSS) without validation or HTML escaping before outputting them into a <style> element in the page head. An authenticated user with Contributor role or above can inject arbitrary CSS by modifying post metadata or block attributes via the WordPress REST API. While JavaScript execution is prevented at this privilege level by WordPress's content filtering, attackers can perform CSS-based attacks including page defacement, UI redressing, forcing external resource loads, and information disclosure through CSS selectors. The vulnerability was patched in version 2.5.1.

## Affected products

- GutenKit GutenKit before 2.5.1

## Timeline

- 2026-09-01: disclosed
- 2026-09-01: patched: version 2.5.1 released

## References

- [https://wordpress.org/plugins](https://wordpress.org/plugins)
- [https://wpscan.com/vulnerability/0e6cd37e-3004-498d-8d8d-21617138888a/](https://wpscan.com/vulnerability/0e6cd37e-3004-498d-8d8d-21617138888a/)