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Vulnerability record · CVE-2026-5127 · published 8 May 2026

CVE-2026-5127: Deserialization of untrusted data vulnerability

The User Frontend: AI Powered Frontend Posting, User Directory, Profile, Membership & User Registration plugin for WordPress is vulnerable to Deserialization of Untrusted Data in versions up to, and including, 4.3.1 This is due to insufficient input validation and type checking on the wpuf_files parameter during form submission, combined with unconditional deserialization via maybe_unserialize() when displaying post content. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject arbitrary PHP objects, which can be leveraged to execute arbitrary code, delete arbitrary files, or perform other malicious actions if a POP chain is present on the target system.

8.8 CVSS 3.1 High EPSS 1.3% · top 30.1% CWE-502 · Deserialization of untrusted data Deferred
8.8CVSS 3.1 base score
1.3%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
19References
17 Jun 2026Last modified by NVD

Description

The User Frontend: AI Powered Frontend Posting, User Directory, Profile, Membership & User Registration plugin for WordPress is vulnerable to Deserialization of Untrusted Data in versions up to, and including, 4.3.1 This is due to insufficient input validation and type checking on the wpuf_files parameter during form submission, combined with unconditional deserialization via maybe_unserialize() when displaying post content. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject arbitrary PHP objects, which can be leveraged to execute arbitrary code, delete arbitrary files, or perform other malicious actions if a POP chain is present on the target system.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

LinkTags
https://plugins.trac.wordpress.org/browser/wp-user-frontend/tags/4.2.10/includes/Ajax/Frontend_Form_Ajax.php#L35
https://plugins.trac.wordpress.org/browser/wp-user-frontend/tags/4.2.10/includes/Ajax/Frontend_Form_Ajax.php#L36
https://plugins.trac.wordpress.org/browser/wp-user-frontend/tags/4.2.10/includes/Traits/FieldableTrait.php#L429
https://plugins.trac.wordpress.org/browser/wp-user-frontend/tags/4.2.10/includes/Traits/FieldableTrait.php#L502
https://plugins.trac.wordpress.org/browser/wp-user-frontend/tags/4.2.10/includes/Traits/FieldableTrait.php#L679
https://plugins.trac.wordpress.org/browser/wp-user-frontend/tags/4.2.10/includes/Traits/FieldableTrait.php#L704
https://plugins.trac.wordpress.org/browser/wp-user-frontend/tags/4.2.10/wpuf-functions.php#L1103
https://plugins.trac.wordpress.org/browser/wp-user-frontend/tags/4.2.10/wpuf-functions.php#L959
https://plugins.trac.wordpress.org/browser/wp-user-frontend/trunk/includes/Ajax/Frontend_Form_Ajax.php#L35
https://plugins.trac.wordpress.org/browser/wp-user-frontend/trunk/includes/Ajax/Frontend_Form_Ajax.php#L36
https://plugins.trac.wordpress.org/browser/wp-user-frontend/trunk/includes/Traits/FieldableTrait.php#L429
https://plugins.trac.wordpress.org/browser/wp-user-frontend/trunk/includes/Traits/FieldableTrait.php#L502
https://plugins.trac.wordpress.org/browser/wp-user-frontend/trunk/includes/Traits/FieldableTrait.php#L679
https://plugins.trac.wordpress.org/browser/wp-user-frontend/trunk/includes/Traits/FieldableTrait.php#L704
https://plugins.trac.wordpress.org/browser/wp-user-frontend/trunk/wpuf-functions.php#L1103
https://plugins.trac.wordpress.org/browser/wp-user-frontend/trunk/wpuf-functions.php#L959
https://plugins.trac.wordpress.org/changeset/3514258/wp-user-frontend/trunk/includes/Traits/FieldableTrait.php
https://plugins.trac.wordpress.org/changeset?old_path=%2Fwp-user-frontend/tags/4.3.1&new_path=%2Fwp-user-frontend/tags/4
https://www.wordfence.com/threat-intel/vulnerabilities/id/2b5d27cc-c6eb-4c5c-8ee1-30483b91c6fd?source=cve

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Source: NIST National Vulnerability Database (record CVE-2026-5127), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.