# CVE-2026-39742: Gutenberg Blocks by Kadence Blocks stored XSS

Source: https://junglewise.ai/threats/cve-2026-39742-improper-neutralization-of-input-during-web-page-generation-cross  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-29. Updated: 2026-10-29  
License: CC BY 4.0 with a link back

CVE-2026-39742 · Severity: medium · CVSS 6.5 · Published 2026-10-29

Gutenberg Blocks by Kadence Blocks is a WordPress plugin that extends the block editor with additional content blocks. A stored cross-site scripting (XSS) vulnerability allows authenticated users with contributor or developer privileges to inject malicious scripts that execute for all site visitors, potentially stealing data or hijacking accounts.

Vendors: [StellarWP](https://junglewise.ai/threats/vendors/stellarwp).

## Quick answers

**Is CVE-2026-39742 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-39742 being exploited in the wild.

**How severe is CVE-2026-39742?** Medium severity, with a CVSS score of 6.5, published 29 October 2026.

**Which products and versions are affected?** StellarWP Gutenberg Blocks by Kadence Blocks through 3.8.0.2.

**Is there a fix for CVE-2026-39742?** Yes: fixed in 3.8.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-39742 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-39742?** Check whether you run StellarWP Gutenberg Blocks by Kadence Blocks 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

- Fixed in 3.8.1

## Technical details

The plugin fails to properly neutralize input during web page generation, allowing stored XSS injection via block content. This requires user interaction and contributor-level or higher privileges to exploit. An attacker with the necessary role can inject persistent malicious scripts that execute in the browsers of all site visitors, potentially leading to session hijacking, credential theft, or malware distribution.

## Affected products

- StellarWP Gutenberg Blocks by Kadence Blocks through 3.8.0.2

## Timeline

- 2026-10-29: disclosed
- 2026-10-29: patched

## References

- [https://wordpress.org/plugins](https://wordpress.org/plugins)
- [https://patchstack.com/database/wordpress/plugin/kadence-blocks/vulnerability/wordpress-gutenberg-blocks-by-kadence-blocks-plugin-3-8-0-2-cross-site-scripting-xss-vulnerability?_s_id=cve](https://patchstack.com/database/wordpress/plugin/kadence-blocks/vulnerability/wordpress-gutenberg-blocks-by-kadence-blocks-plugin-3-8-0-2-cross-site-scripting-xss-vulnerability?_s_id=cve)