---
id: "CVE-2026-92798"
kind: "vulnerability"
aliases: ["CVE-2026-92798"]
title: "WordPress User Registration plugin: unauthenticated shortcode execution via referer header"
severity: "high"
cvss: 8.1
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["package", "self-hosted", "user-registration-plugin", "wordpress"]
not_affected_if: ["default-config", "plugin-updated"]
published_at: "2026-10-17T04:17:10+00:00"
first_seen_at: "2026-10-23T21:57:14+00:00"
updated_at: "2026-10-25T03:06:39+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-92798", "first_seen_at": "2026-10-23T21:57:14+00:00"}]
---

# WordPress User Registration plugin: unauthenticated shortcode execution via referer header

The User Registration & Membership WordPress plugin up to and including 5.2.8 passes the HTTP Referer header into a restricted-content message without stripping shortcode delimiters, then runs that message through shortcode processing. An unauthenticated visitor can make any registered WordPress shortcode execute on a restricted page that uses the {{referrer_url}} smart tag.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed version of the User Registration & Membership plugin (`wp plugin get user-registration --field=version` or the Plugins screen) and see whether it is `5.2.8` or lower.
- Search Content Restriction messages for the `{{referrer_url}}` smart tag.

## Fix

- Update the User Registration & Membership plugin to a version above `5.2.8`; the fixed version number is unknown from the sources.
- Until updated, remove `{{referrer_url}}` from restricted-content messages.

## Timeline

- 2026-10-23T21:57:14+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-92798

## From the sources

The User Registration & Membership plugin for WordPress is vulnerable to Arbitrary Shortcode Execution in versions up to, and including, 5.2.8 This is due to insufficient input sanitization in the 'referrer_url' branch of UR_Smart_Tags::process(), where the attacker-controlled HTTP_REFERER header is only passed through sanitize_text_field() — which does not strip WordPress shortcode delimiters — before being substituted into a Content Restriction message that is subsequently executed via apply_shortcodes()/do_shortcode(). This makes it possible for unauthenticated attackers to execute arbitrary registered shortcodes on any restricted page whose message uses the supported {{referrer_url}} smart tag.

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