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CRITICAL

CVE-2026-15826

User Profile Builder <= 3.16.4 - Unauthenticated Authentication Bypass via Type Confusion to Administrator Account Takeover via 'username' Parameter

CVSS v3

9.8

CRITICAL

EPSS Score

3.9 %

exploit probability, as of 2026-09-29

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Description

The User Profile Builder plugin for WordPress is vulnerable to Authentication Bypass via Type Confusion in versions up to, and including, 3.16.4. This is due to the wppb_log_in_user() function calling absint() on the return value of wp_insert_user() before performing an is_wp_error() check — when a registration is submitted with a 61–70 character username, WordPress core rejects it with a WP_Error object, but absint() coerces that object to the integer 1 before the error check can short-circuit

Technical details

Published
2026-08-15
Last Modified
2026-08-15

Frequently asked questions

What is CVE-2026-15826?

The User Profile Builder plugin for WordPress is vulnerable to Authentication Bypass via Type Confusion in versions up to, and including, 3.16.4. This is due to the wppb_log_in_user() function calling absint() on the return value of wp_insert_user() before performing an is_wp_error() check — when a registration is submitted with a 61–70 character username, WordPress core rejects it with a WP_Error object, but absint() coerces that object to the integer 1 before the error check can short-circuit

Is CVE-2026-15826 actively exploited?

Active exploitation of CVE-2026-15826 has not been confirmed. Its EPSS score was 3.9% on 2026-09-29, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-15826?

CVE-2026-15826 has a CVSS v3 base score of 9.8 (CRITICAL severity).

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