CVE-2025-26998 Overview
CVE-2025-26998 is a stored Cross-Site Scripting (XSS) vulnerability in the SKT Blocks WordPress plugin developed by sonalsinha21. The flaw exists in the Gutenberg-based page builder plugin skt-blocks and affects all versions up to and including 1.8. Attackers with contributor-level access or higher can inject malicious scripts that persist in stored page content. When other users, including administrators, view the affected pages, the script executes in their browser context. The issue is tracked under CWE-79 for Improper Neutralization of Input During Web Page Generation.
Critical Impact
Authenticated attackers can inject persistent JavaScript that executes in the browsers of site visitors and administrators, enabling session theft, forced administrative actions, and site defacement.
Affected Products
- SKT Blocks (skt-blocks) WordPress plugin — all versions through 1.8
- WordPress sites using the Gutenberg-based page builder from sktthemes
- Any site where untrusted contributor accounts can author block content
Discovery Timeline
- 2025-04-15 - CVE-2025-26998 published to the National Vulnerability Database
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-26998
Vulnerability Analysis
The vulnerability stems from improper neutralization of user-supplied input rendered by SKT Blocks page builder components. The plugin fails to sanitize or escape attribute values and inline content passed through its Gutenberg blocks before they are written into the page markup. Because the payload is stored in the WordPress database and served to every visitor of the affected page, this is a persistent (stored) XSS rather than a reflected variant.
Exploitation requires low privileges and user interaction. An authenticated user with block-editing rights supplies the malicious payload, and the script executes when another user loads the page. Because the vulnerability crosses privilege boundaries (contributor content viewed by administrators), the CVSS scope is marked as changed. Successful exploitation yields limited confidentiality and integrity impact, including cookie theft, forced browser actions, and administrative UI manipulation.
Root Cause
The root cause is missing output encoding within block render callbacks. WordPress provides sanitization helpers such as esc_attr(), esc_html(), and wp_kses_post(), but the affected SKT Blocks components emit user-controlled strings directly into HTML attributes or element bodies. Any input containing <script> tags, on* event handlers, or javascript: URIs is preserved verbatim in the rendered output.
Attack Vector
An attacker authenticates as a contributor or higher, edits a page or post using an SKT Blocks component, and stores a payload in a vulnerable field. The payload persists in wp_posts and executes each time a victim renders the page. Because the CVSS scope is changed, execution occurs in the security context of the WordPress admin origin, giving the attacker access to authenticated session data and administrative endpoints. No verified public proof-of-concept is available at this time. Refer to the Patchstack advisory for additional technical detail.
Detection Methods for CVE-2025-26998
Indicators of Compromise
- Post or page content in wp_posts containing <script> tags, onerror=, onload=, or javascript: URIs within SKT Blocks shortcodes or block markup
- Unexpected outbound requests from administrator browsers to attacker-controlled domains shortly after loading pages built with SKT Blocks
- New or modified administrator accounts, plugin installations, or option changes correlated with contributor edits to SKT Blocks content
Detection Strategies
- Audit all posts and pages authored or edited by non-administrator users for HTML event handlers and script tags within SKT Blocks component attributes
- Deploy a Web Application Firewall (WAF) rule that flags block attribute payloads containing script primitives before they are stored
- Monitor WordPress audit logs for edits to published content by contributor and author roles, particularly on sites where the plugin version is at or below 1.8
Monitoring Recommendations
- Ingest WordPress access logs and authentication events into a centralized SIEM for correlation with content-modification events
- Alert on Content Security Policy (CSP) violation reports originating from pages built with the SKT Blocks plugin
- Track plugin version inventory across WordPress fleets to identify hosts still running vulnerable skt-blocks builds
How to Mitigate CVE-2025-26998
Immediate Actions Required
- Update the SKT Blocks plugin to a version later than 1.8 as soon as the vendor publishes a fixed release
- Restrict block-editing privileges to trusted users and review the contributor role assignments on affected sites
- Purge any stored payloads by reviewing recent edits and stripping suspicious HTML from SKT Blocks content
Patch Information
The advisory published by Patchstack indicates the vulnerability affects SKT Blocks versions through 1.8. Administrators should consult the Patchstack vulnerability record and the plugin's WordPress.org page for the latest fixed release. If no patched version is available, disable the plugin until a fix is released.
Workarounds
- Disable the SKT Blocks plugin on sites that permit untrusted content authors
- Deploy a strict Content Security Policy that disallows inline script execution and restricts script sources to trusted origins
- Apply a virtual patch through a WAF that blocks HTML event handlers and script tags in POST bodies targeting /wp-admin/post.php and the REST API editor endpoints
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
