Sticky <= 2.5.6 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'readmoretext' Shortcode Attribute
Strategic Overview
- Status
- Unpatched
- Affected Plugin
- Sticky
- Affected Version
<= 2.5.6- CVSS
- 6.4Medium
- Weakness type
- CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CVE
CVE-2026-6397
At a glance
CVE-2026-6397 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Sticky WordPress plugin, affecting versions <= 2.5.6. It carries a CVSS score of 6.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Contributor level or above. No fixed release has been reported yet; treat installations running this software as exposed. Disclosed May 2026, reported by zaim.
Vulnerability Overview
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.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user.
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Sticky <= 2.5.6 carries this weakness at cvmh_sticky_front_render(), and reaching it takes an account at Contributor level or above. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.
Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. No fixed build of this plugin is recorded for Sticky yet, so installs running <= 2.5.6 stay exposed until the vendor ships one.
Remediation
No known patch available. Please review the vulnerability's details in depth and employ mitigations based on your organization's risk tolerance. It may be best to uninstall the affected software and find a replacement.
How does WordSec protect against this?
An attacker needs Contributor access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. No patched version is recorded yet, which is the case where a filtering layer matters most, because there is nothing to update to.
- Firewall
- Alerts
External References
Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C