Vulnerability in Post Snippets – Custom WordPress Code Snippets Customizer — CVE-2026-77871

What to do now

Update Post Snippets – Custom WordPress Code Snippets Customizer to 4.2.5 or later.

Affected versions

• Everything up to and including 4.2.4

The Post Snippets – Custom WordPress Code Snippets Customizer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Shortcode Attributes in all versions up to, and including, 4.2.4 due to insufficient input sanitization and output escaping. 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. Entity-encoded payloads such as <script>...</script> survive WordPress's wp_kses_post on-save sanitization because kses does not decode HTML entities, and are only converted back into executable HTML tags at render time by the plugin's own shortcode filter. This requires snippet shortcodes to be enabled.

This description is reproduced verbatim from the public vulnerability record.

• https://www.wordfence.com/threat-intel/vulnerabilities/id/a46c37f4-245d-423f-bdad-296fdf377ecc?source=api-prod

Part of this record comes from Wordfence Intelligence. Original: https://www.wordfence.com/threat-intel/vulnerabilities/id/a46c37f4-245d-423f-bdad-296fdf377ecc
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