What’s Vulnerable › Vulnerabilities

CVE-2026-4125: WPMK Block <= 1.0.1 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode Attributes

• Severity: medium (CVSS 6.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-22 · updated 2026-06-17
• Weakness: CWE-79

Description

The WPMK Block plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'class' shortcode attribute in all versions up to and including 1.0.1. This is due to insufficient input sanitization and output escaping on user-supplied shortcode attributes. Specifically, in the wpmk_block_shortcode() function, the 'class' attribute is extracted from user-controllable shortcode attributes and directly concatenated into an HTML div element's class attribute without any escaping (e.g., esc_attr()). 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.

Affected products

• wpmkorg WPMK Block: through 1.0.1

References

• https://plugins.trac.wordpress.org/browser/wpmk-block/tags/1.0.1/classes/wpmk-block-class.php#L82
• https://plugins.trac.wordpress.org/browser/wpmk-block/tags/1.0.1/classes/wpmk-block-class.php#L97
• https://plugins.trac.wordpress.org/browser/wpmk-block/trunk/classes/wpmk-block-class.php#L82
• https://plugins.trac.wordpress.org/browser/wpmk-block/trunk/classes/wpmk-block-class.php#L97
• https://www.wordfence.com/threat-intel/vulnerabilities/id/5e397c7a-2aef-4c23-a224-e324ea4bb4b1?source=cve

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