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.

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

Q: 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.

Q: How is CVE-2026-15420 attacked?

It is attacked over the network, in a software library.

Q: 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.

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. 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

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