CVE-2026-5399: XSS (CVSS 6.4)

Description

The Redux Framework plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Slider field in User Profile settings in versions up to and including 4.5.13.1. This is due to insufficient input sanitization in the user_meta_save() function (which only sanitizes array values, not scalar values) and improper output escaping in the Redux_Slider::render() method, which outputs slider values into unquoted HTML attributes. The vulnerability also exploits the fact that the clean_default() method only casts values to numeric types when they are empty or out of bounds, allowing malicious strings like '1 tabindex=0 autofocus onfocus=alert(1) x=' to pass validation through PHP's loose type comparison. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject arbitrary web scripts into their user profile that will execute whenever an Administrator navigates to view the attacker's profile page.

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CVSS v3.1 Score

6.4

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0033

Probability of exploitation

0.27%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

https://github.com/reduxframework/redux-framework/pull/4112/changes https://plugins.trac.wordpress.org/browser/redux-framework/tags/4.5.10/redux-core/inc/extensions/users/class-redux-extension-users.php#L1018 https://plugins.trac.wordpress.org/browser/redux-framework/tags/4.5.10/redux-core/inc/fields/slider/class-redux-slider.php#L311 https://plugins.trac.wordpress.org/browser/redux-framework/trunk/redux-core/inc/extensions/users/class-redux-extension-users.php#L1018 https://plugins.trac.wordpress.org/browser/redux-framework/trunk/redux-core/inc/fields/slider/class-redux-slider.php#L311 https://www.wordfence.com/threat-intel/vulnerabilities/id/31c554cf-eee9-45a8-8fb6-198978620204?source=cve

Frequently Asked Questions

What is CVE-2026-5399? +

The Redux Framework plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Slider field in User Profile settings in versions up to and including 4.5.13.1. This is due to insufficient input sanitization in the user_meta_save() function (which only sanitizes array values, not scalar values) and improper output escaping in the Redux_Slider::render() method, which outputs slider values into unquoted HTML attributes. The vulnerability also exploits the fact that the clean_default() method only casts values to numeric types when they are empty or out of bounds, allowing malicious strings like '1 tabindex=0 autofocus onfocus=alert(1) x=' to pass validation through PHP's loose type comparison. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject arbitrary web scripts into their user profile that will execute whenever an Administrator navigates to view the attacker's profile page. It has a CVSS v3.1 base score of 6.4 (MEDIUM).

How severe is CVE-2026-5399? +

CVE-2026-5399 has a CVSS v3.1 score of 6.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0033, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-5399? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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