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Cross-Site Request Forgery (CSRF)Weakness · CWE-352

CVE-2026-4131

MEDIUM · 6.1 CVSS v3.1 Published 2026-04-22
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The WP Responsive Popup + Optin plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to and including 1.4. This is due to the settings form on the admin page (wpo_admin_page.php) lacking nonce generation (wp_nonce_field) and verification (wp_verify_nonce/check_admin_referer). This makes it possible for unauthenticated attackers to update all plugin settings including the 'wpo_image_url' parameter via a forged request, granted they can trick a site administrator into performing an action such as clicking a link.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The WP Responsive Popup + Optin WordPress plugin lacks anti-CSRF tokens (nonce fields) on its admin settings form in wpo_admin_page.php. This allows unauthenticated attackers to forge requests that modify plugin settings, including the 'wpo_image_url' parameter, by tricking authenticated administrators into clicking malicious links.

MitigationApply vendor patch when available; until then, admin users should avoid clicking untrusted links to prevent CSRF attacks that could modify plugin settings.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify WP Responsive Popup + Optin plugin is installed
    In WordPress admin, go to Plugins > Installed Plugins and look for 'WP Responsive Popup + Optin' or check wp-content/plugins/ directory for a folder containing 'popup' or 'wpo' in the name
    Affected if The plugin is installed and active
  2. Identify the installed plugin version
    Check the plugin's main PHP file header for 'Version:' comment, or look in WordPress plugin repository for the installed version, or inspect the plugin folder for a readme.txt file containing version info
    Affected if Installed version falls within any affected range (check WordPress plugin repository for vulnerable versions)
  3. Locate the vulnerable file
    Navigate to wp-content/plugins/[plugin-folder]/includes/wpo_admin_page.php (path may vary by installation)
    Affected if The file wpo_admin_page.php exists in the plugin directory
  4. Check for missing nonce validation in admin form
    Open wpo_admin_page.php and search for the admin settings form handling code; look for 'wpo_image_url' parameter processing and check if wp_nonce_field(), wp_verify_nonce(), or check_admin_referer() is called before processing this parameter
    Affected if The form processing for 'wpo_image_url' lacks nonce verification (no wp_nonce_field in the form and no nonce check before processing)
  5. Inspect the form output for nonce field
    View the page source when visiting the plugin's admin settings page; search for an input field with name containing 'nonce' or '_wpnonce' related to the settings form
    Affected if The admin settings form does not contain a hidden nonce field (input type="hidden" with nonce-related name)

You are affected if the WP Responsive Popup + Optin plugin is installed and its admin settings form in wpo_admin_page.php processes the 'wpo_image_url' parameter without verifying a nonce token.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor patch when available; until then, admin users should avoid clicking untrusted links to prevent CSRF attacks that could modify plugin settings.

Recommended fix Moderate confidence

Version 1.5 or later of WP Responsive Popup + Optin plugin

  1. Check the current version of the WP Responsive Popup + Optin plugin installed on your WordPress site
  2. Navigate to Plugins > Installed Plugins in the WordPress admin dashboard
  3. If the installed version is 1.4 or earlier, update the plugin to the latest available version (version 1.5 or later, which contains the CSRF fix)
  4. After updating, verify that the plugin settings remain intact and functioning correctly
  5. As a general security practice, ensure WordPress core and all other plugins are also kept up to date

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-4131 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data