CVE-2026-13439
Privilege escalation
- Published21 Jul 2026
Description
The Easy Form Builder by WhiteStudio plugin for WordPress is vulnerable to Unauthenticated Privilege Escalation to Administrator in versions up to, and including, 4.0.11 This is due to the password recovery flow using the publicly-visible session identifier ('sid') as the password reset token stored in wp_emsfb_temp_links, combined with a publicly-accessible nonce refresh endpoint (Emsfb/v1/nonce/refresh) that issues valid WordPress REST nonces to unauthenticated visitors. This makes it possible for unauthenticated attackers to reset the password of any WordPress user — including administrators — by scraping the public sid from a published login form page, submitting a recovery request for any known user email via Emsfb/v1/forms/message/add, and then calling Emsfb/v1/forms/recovery/efb_set_password with the known sid to set an arbitrary new password and gain full administrator access.
CVSS 3.1 breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HRemediation
No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.
References
- https://plugins.trac.wordpress.org/browser/easy-form-builder/trunk/includes/class-Emsfb-public.php#L1587
- https://plugins.trac.wordpress.org/browser/easy-form-builder/trunk/includes/class-Emsfb-public.php#L5024
- https://plugins.trac.wordpress.org/browser/easy-form-builder/trunk/includes/class-Emsfb-public.php#L5060
- https://plugins.trac.wordpress.org/browser/easy-form-builder/trunk/includes/class-Emsfb-public.php#L623
- https://plugins.trac.wordpress.org/browser/easy-form-builder/trunk/includes/class-Emsfb-public.php#L96
- https://plugins.trac.wordpress.org/changeset/3588226/easy-form-builder/trunk/includes/class-Emsfb-public.php
- https://plugins.trac.wordpress.org/changeset?old_path=%2Feasy-form-builder/tags/4.0.11&new_path=%2Feasy-form-builder/tags/4.0.12
- https://www.wordfence.com/threat-intel/vulnerabilities/id/df8326b6-a443-4f76-a755-49f89af74d7e?source=cve
Related CVEs
Recent high-severity vulnerabilities sharing a weakness type.
Frequently asked
Is CVE-2026-13439 being actively exploited?
CVE-2026-13439 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.71%.
How severe is CVE-2026-13439?
CVE-2026-13439 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.71% probability of exploitation.
How do I fix CVE-2026-13439?
Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.
How Secuno handles this
Secuno correlates vulnerabilities like CVE-2026-13439 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.
Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.