CVE-2026-110018

aBlocks <= 2.17.0 - Authenticated (Contributor+) Privilege Escalation to 'roleSlug' Block Attribute

2026-10-23 21:31
Wordfence PRISM

Strategic Overview

At a glance

CVE-2026-110018 is a high-severity Improper Privilege Management vulnerability in the aBlocks WordPress plugin, affecting versions <= 2.17.0. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account at Contributor level or above. The issue is fixed in version 2.18.0; sites on affected versions should update now. Disclosed October 2026, reported by Wordfence PRISM.

Vulnerability Overview

The aBlocks – Gutenberg Blocks, User Dashboard Builder, Popup Builder, Form Builder & Animation Builder plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 2.17.0 via the `/ablocks/v1/form-builder/registration` REST endpoint. The vulnerability exists because the endpoint is registered with `permission_callback => __return_true` and the `register()` handler reads `roleSlug` directly from attacker-controlled block attributes in `post_content` without ever verifying that the block's `formType` is `registration` — a condition that `RegistrationFormSanitizer::verify()` imposes only at save-time, meaning a Contributor can preserve an arbitrary `roleSlug` by saving a block with `formType='login'` and then triggering the endpoint via a valid `wp_rest` nonce and post-ownership check. This makes it possible for authenticated attackers, with Contributor-level access and above, to escalate their WordPress role to Editor or any other non-administrator role and receive a fully authenticated session at the elevated privilege level via `WP_User::set_role()` and `wp_set_auth_cookie()`. Escalation is bounded below administrator-tier roles because `is_safe_registration_role()` rejects any role holding `manage_options`, `edit_users`, `delete_users`, `create_users`, `promote_users`, or `edit_theme_options`, meaning the highest practically reachable role on a standard WordPress installation is Editor.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-269: Improper Privilege Management

aBlocks <= 2.17.0 carries this weakness at login, and reaching it takes an account at Contributor level or above. Improper privilege management means the code lets an account end up with capabilities its role should not have.

It converts a low-privileged account into an administrative one, which makes every other restriction on the site irrelevant. For aBlocks the fix is 2.18.0: builds <= 2.17.0 are affected, anything from 2.18.0 onward is not.

Remediation

Update to version 2.18.0, or a newer patched version

How does WordSec protect against this?

Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: aBlocks 2.18.0 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C