CVE-2026-6397: Sticky <= 2.5.6 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'readmoretext' Shortcode Attribute
The Sticky plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `cvmh-sticky` shortcode `readmoretext` attribute in versions up to and including 2.5.6. This is due to insufficient input sanitization and output escaping in the `cvmh_sticky_front_render()` function — the `readmoretext` attribute value is passed through `apply_filters()` and directly concatenated into the HTML output without any escaping function such as `esc_html()`. 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 a page containing the injected shortcode.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-6397?
The severity of CVE-2026-6397 is medium with a score of 6.4.
How do I fix CVE-2026-6397?
To fix CVE-2026-6397, update the Sticky plugin to a version later than 2.5.6 that addresses the vulnerability.
What type of vulnerability is identified in CVE-2026-6397?
CVE-2026-6397 is identified as a Stored Cross-Site Scripting (XSS) vulnerability.
Which versions of the Sticky plugin are affected by CVE-2026-6397?
The vulnerability affects all versions of the Sticky plugin for WordPress up to and including 2.5.6.
What causes the vulnerability in CVE-2026-6397?
The vulnerability in CVE-2026-6397 is caused by insufficient input sanitization and output escaping in the shortcode functionality.