Is CVE-2026-4883 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-4883 being exploited in the wild.

How severe is CVE-2026-4883?

Critical severity, with a CVSS score of 9.8, published 19 May 2026.

Which products and versions are affected?

Piotnet Forms up to, and including, 2.1.40.

Is there a fix for CVE-2026-4883?

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-2026-4883 attacked?

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

Am I affected by CVE-2026-4883?

Check whether you run Piotnet Forms 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-2026-4883: Piotnet Forms arbitrary file upload in piotnetforms_ajax_form_builder

CVE-2026-4883 · Severity: critical · CVSS 9.8 · Published 2026-05-19

Piotnet Forms is a WordPress plugin used to build custom forms for websites. A security flaw allows unauthenticated attackers to upload malicious files to the web server because the plugin fails to properly restrict certain file types. If a form on the site includes a file upload field, an attacker could take full control of the website, potentially leading to data theft or a complete service shutdown.

Vendors: Piotnet.

Quick answers

Is CVE-2026-4883 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-4883 being exploited in the wild.
How severe is CVE-2026-4883?: Critical severity, with a CVSS score of 9.8, published 19 May 2026.
Which products and versions are affected?: Piotnet Forms up to, and including, 2.1.40.
Is there a fix for CVE-2026-4883?: 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-2026-4883 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-4883?: Check whether you run Piotnet Forms 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 Piotnet Forms plugin for WordPress (versions up to 2.1.40) contains an unrestricted file upload vulnerability within the 'piotnetforms_ajax_form_builder' function. The root cause is an incomplete extension blacklist that filters common extensions like .php and .exe but fails to block dangerous alternatives such as .phar or .phtml. An unauthenticated remote attacker can exploit this by submitting a form that contains a file upload field, allowing them to upload malicious scripts to the server. Successful exploitation can lead to remote code execution (RCE) and full system compromise.

Affected products

Piotnet Piotnet Forms up to, and including, 2.1.40

Timeline

2026-05-19: disclosed: CVE published to NVD

References

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