EUVD-2026-24666
GHSA-f4p3-578m-v245
Severity by source
AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
Lifecycle Timeline
4DescriptionCVE.org
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.
AnalysisAI
Stored Cross-Site Scripting in WPMK Block plugin for WordPress up to version 1.0.1 allows authenticated attackers with Contributor-level access to inject arbitrary web scripts via the 'class' shortcode attribute, which is directly concatenated into HTML without proper escaping. The vulnerability affects all versions through 1.0.1 due to insufficient input sanitization in the wpmk_block_shortcode() function, enabling persistent XSS attacks that execute whenever users access compromised pages.
Technical ContextAI
The WPMK Block plugin is a WordPress extension that processes shortcodes with user-supplied attributes. The vulnerability exists in the wpmk_block_shortcode() function, which extracts the 'class' attribute from shortcode parameters and directly embeds it into an HTML div element's class attribute without applying WordPress security functions like esc_attr(). This represents a classic Stored XSS vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation) where user input flows through the shortcode parser directly into the DOM without sanitization or output encoding. The affected CPE indicates all versions of the wpmk_block plugin from the wpmkorg vendor are potentially impacted through version 1.0.1.
RemediationAI
WordPress administrators should update the WPMK Block plugin immediately to a patched version released after 1.0.1; check the WordPress plugin repository for the latest available version, as the patch version number is not specified in available sources. The root fix requires the plugin developer to implement proper output escaping by applying the esc_attr() WordPress function to the 'class' attribute before concatenation into the HTML div element (line 97 in the affected code at https://plugins.trac.wordpress.org/browser/wpmk-block/tags/1.0.1/classes/wpmk-block-class.php#L97). As a temporary workaround on sites unable to immediately update, restrict the Contributor role to trusted users only and monitor posts and pages for unusual shortcode usage; disable the WPMK Block plugin entirely if no users require Contributor access. Sites running version 1.0.1 or earlier should prioritize this update to prevent persistent XSS injection.
Same weakness CWE-79 – Cross-site Scripting (XSS)
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External POC / Exploit Code
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