$ cve CVE-2026-15826 JSON

CVE-2026-15826

9.8

CRITICAL · CVSS 3.1 · EPSS 3.9% (pctl 90)

In your normal cycle

Critical by CVSS (9.8), but no sign of active exploitation.

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 execution, causing the plugin to bind and return a transient-backed autologin nonce tied to user ID 1. This makes it possible for unauthenticated attackers to log in as the site's Administrator account (user ID 1), resulting in full administrative takeover of the site.

Scoring

CVSS	9.8 (CRITICAL, v3.1)
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS	3.9% — more likely to be exploited than 90% of all CVEs
Weakness	CWE-704
On CISA KEV	no
Public exploit	none known
Published	2026-08-15
Last modified	2026-08-20

References

→ the Explorer · watch your stack · NVD