CVE-2026-15420

Nexter Blocks <= 5.0.0 - Authenticated (Subscriber+) Path Traversal to Arbitrary CSS/JS File Deletion via 'plus_name' Parameter

2026-07-23 14:21
Wordfence PRISM

Strategic Overview

Status
Patched in 5.0.1
Affected Plugin
Nexter Blocks – Gutenberg Blocks, Page Builder & AI Website Builder
Affected Version
<= 5.0.0
CVSS
4.3Medium
Weakness type
CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CVE
CVE-2026-15420
View all Nexter Blocks – Gutenberg Blocks, Page Builder & AI Website Builder vulnerabilities

At a glance

CVE-2026-15420 is a medium-severity Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in the Nexter Blocks WordPress plugin, affecting versions <= 5.0.0. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Subscriber level or above. The issue is fixed in version 5.0.1; sites on affected versions should update now. Disclosed July 2026, reported by Wordfence PRISM.

Vulnerability Overview

The Nexter Blocks – Gutenberg Blocks, Page Builder & AI Website Builder plugin for WordPress is vulnerable to Directory Traversal in all versions up to, and including, 5.0.0 via the 'plus_name' parameter. This makes it possible for authenticated attackers, with subscriber-level access and above, to delete arbitrary JS/CSS files on the server, which can lead to denial of service or destruction of critical plugin and theme assets.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user.

CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Nexter Blocks <= 5.0.0 carries this weakness at plus_name, and reaching it takes an account at Subscriber level or above. Path traversal happens when user-controlled text is used to build a filesystem path without being constrained to an intended directory, so sequences like ../ walk the resolved path somewhere else.

Depending on the operation, it means reading files outside the intended folder — wp-config.php being the usual target — or writing to and deleting paths the web server can touch. For Nexter Blocks the fix is 5.0.1: builds <= 5.0.0 are affected, anything from 5.0.1 onward is not.

Remediation

Update to version 5.0.1, or a newer patched version

How does WordSec protect against this?

An attacker needs Subscriber access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Nexter Blocks 5.0.1 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-15420https://www.wordfence.com/threat-intel/vulnerabilities/id/85550779-fd46-4130-92f1-b291d4e86b21https://nvd.nist.gov/vuln/detail/CVE-2026-15420

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C