CVE-2026-18344: XSS (CVSS 6.1)

Description

The Wp Responsive Thumbnail Slider plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'id' parameter in versions up to, and excluding, 1.1.53. This is due to insufficient input sanitization and output escaping in the responsive_thumbnail_image_management() function, which echoes $_GET['id'] directly into a double-quoted HTML attribute with no esc_attr() call. The only guard is a loose PHP numeric comparison ($_GET['id']>0) that a string beginning with a numeric prefix trivially satisfies, and the addslashes() applied by wp_magic_quotes() is inert in HTML-attribute context because backslash is not an HTML escape character. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a specially crafted link.

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CVSS v3.1 Score

6.1

MEDIUM

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

EPSS — Exploit Prediction

0.0022

Probability of exploitation

0.12%

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://plugins.trac.wordpress.org/browser/wp-responsive-thumbnail-slider/trunk/wp-responsive-images-thumbnail-slider.php#L1274 https://plugins.trac.wordpress.org/browser/wp-responsive-thumbnail-slider/trunk/wp-responsive-images-thumbnail-slider.php#L1275 https://www.wordfence.com/threat-intel/vulnerabilities/id/c7370cbc-f681-49d7-9330-762443202529?source=cve

Frequently Asked Questions

What is CVE-2026-18344? +

The Wp Responsive Thumbnail Slider plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'id' parameter in versions up to, and excluding, 1.1.53. This is due to insufficient input sanitization and output escaping in the responsive_thumbnail_image_management() function, which echoes $_GET['id'] directly into a double-quoted HTML attribute with no esc_attr() call. The only guard is a loose PHP numeric comparison ($_GET['id']>0) that a string beginning with a numeric prefix trivially satisfies, and the addslashes() applied by wp_magic_quotes() is inert in HTML-attribute context because backslash is not an HTML escape character. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a specially crafted link. It has a CVSS v3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2026-18344? +

CVE-2026-18344 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0022, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-18344? +

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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CVE-2026-18344