---
id: CVE-2026-104732
title: >-
  The Advanced IP Blocker plugin for WordPress is vulnerable to Authentication
  Bypass in all versions up to, and including, 8.13.13 The vulnerability exists
  because `handle_login_action()` performs no server-side check — via transient,
  ses…
summary: >-
  The Advanced IP Blocker plugin for WordPress is vulnerable to Authentication
  Bypass in all versions up to, and including, 8.13.13 The vulnerability exists
  because `handle_login_action()` performs no server-side check — via transient,
  ses…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-287
published: '2026-10-10'
updated: '2026-10-10'
sourceUpdated: '2026-10-10T04:18:08.493'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-104732'
references:
  - url: >-
      https://plugins.trac.wordpress.org/browser/advanced-ip-blocker/tags/8.13.13/includes/class-advaipbl-2fa-manager.php#L71
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/advanced-ip-blocker/tags/8.13.13/includes/class-advaipbl-main.php#L519
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/advanced-ip-blocker/tags/8.13.13/includes/class-advaipbl-main.php#L6875
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/advanced-ip-blocker/tags/8.13.13/includes/class-advaipbl-main.php#L6912
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/browser/advanced-ip-blocker/tags/8.13.13/includes/class-advaipbl-main.php#L7022
    label: security@wordfence.com
  - url: >-
      https://plugins.trac.wordpress.org/changeset/3725139/advanced-ip-blocker/trunk/includes/class-advaipbl-main.php
    label: security@wordfence.com
  - url: >-
      https://www.wordfence.com/threat-intel/vulnerabilities/id/d080845b-6814-4b10-a3ab-1f5aa1d09132?source=cve
    label: security@wordfence.com
tags:
  - nvd
ingestedAt: '2026-10-10T04:21:57.822Z'
---

## Overview

The Advanced IP Blocker plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 8.13.13 The vulnerability exists because `handle_login_action()` performs no server-side check — via transient, session marker, or equivalent — that a requester completed step-1 password authentication before processing a step-2 TOTP submission for the POSTed `user_id`; compounding this, an error branch in the function unconditionally mints a fresh `advaipbl-2fa-interim-{user_id}` nonce and delivers it in a `Location` header to any unauthenticated caller, after which `display_2fa_login_form_step_2()` renders a valid `advaipbl-2fa-verify-{user_id}` nonce in HTML — both nonces computed against a fixed `uid=0` empty-session context and therefore fully reusable by the attacker across subsequent requests. This makes it possible for unauthenticated attackers to bypass authentication entirely for any 2FA-enabled account, including administrators, by brute-forcing an unthrottled 6-digit TOTP code (no attempt counter, no account lockout, and no `wp_login_failed` firing) and receiving a fully authenticated session cookie via `wp_set_auth_cookie` without ever supplying the account password, resulting in complete site takeover. Exploitation requires only a known `user_id` for an account that has the plugin's 2FA feature enabled.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.