# CVE-2026-15420: POSIMYTH Nexter Blocks directory traversal in plus_name parameter

Source: https://junglewise.ai/threats/cve-2026-15420-posimyth-nexter-blocks-directory-traversal-in-plus-name-parameter  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-24. Updated: 2026-07-24  
License: CC BY 4.0 with a link back

CVE-2026-15420 · Severity: medium · CVSS 4.3 · Published 2026-07-24

Nexter Blocks is a WordPress plugin used to build and design websites. A security flaw allows logged-in users with low-level permissions to delete important website files, such as those controlling the site's appearance and functionality. This can lead to the website becoming unavailable or appearing broken to visitors.

Technologies: [POSIMYTH Innovations Nexter Blocks](https://junglewise.ai/threats/technologies/nexter-blocks). Vendors: [POSIMYTH Innovations](https://junglewise.ai/threats/vendors/posimyth-innovations).

## Quick answers

**Is CVE-2026-15420 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-15420 being exploited in the wild.

**How severe is CVE-2026-15420?** Medium severity, with a CVSS score of 4.3, published 24 July 2026.

**Which products and versions are affected?** POSIMYTH Innovations Nexter Blocks <= 5.0.0.

**Is there a fix for CVE-2026-15420?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-15420 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-15420?** Check whether you run POSIMYTH Innovations Nexter 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.

## Technical details

The Nexter Blocks plugin for WordPress is vulnerable to directory traversal in all versions up to and including 5.0.0. The flaw exists within the 'plus_name' parameter in the tp-registered-blocks.php component, where insufficient input validation allows for path manipulation. An authenticated attacker with subscriber-level permissions or higher can exploit this to delete arbitrary JavaScript or CSS files on the server. This can result in a denial of service by destroying critical plugin or theme assets. A patch appears to be available in versions following 5.0.0.

## Affected products

- posimyththemes Nexter Blocks – Gutenberg Blocks, Page Builder & AI Website Builder <= 5.0.0

## Timeline

- 2026-07-24: disclosed
- 2026-07-24: advisory

## References

- [https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.14/classes/tp-registered-blocks.php](https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.14/classes/tp-registered-blocks.php)
- [https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.14/classes/tp-registered-blocks.php](https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.14/classes/tp-registered-blocks.php)
- [https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.14/classes/tp-registered-blocks.php](https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.14/classes/tp-registered-blocks.php)
- [https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.14/classes/tp-registered-blocks.php](https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.14/classes/tp-registered-blocks.php)
- [https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.17/classes/tp-registered-blocks.php](https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.17/classes/tp-registered-blocks.php)
- [https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.17/classes/tp-registered-blocks.php](https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.17/classes/tp-registered-blocks.php)
- [https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.17/classes/tp-registered-blocks.php](https://plugins.trac.wordpress.org/browser/the-plus-addons-for-block-editor/tags/4.7.17/classes/tp-registered-blocks.php)

## Related threats

- [Nexter Blocks WordPress plugin Stored XSS in commentIcon parameter](https://junglewise.ai/threats/cve-2026-6740-nexter-blocks-wordpress-plugin-stored-xss-in-commenticon-parameter)
- [POSIMYTH Nexter Blocks sensitive data exposure in WordPress plugin](https://junglewise.ai/threats/cve-2026-39516-posimyth-nexter-blocks-sensitive-data-exposure-in-wordpress)