CVE-2025-26738 Overview
CVE-2025-26738 is a DOM-Based Cross-Site Scripting (XSS) vulnerability in the Graham Quick Interest Slider WordPress plugin. The flaw stems from improper neutralization of input during web page generation, classified under [CWE-79]. Affected versions include Quick Interest Slider through 3.1.5. Attackers with low privileges can inject malicious scripts that execute in the browser context of victims who interact with a crafted request. The vulnerability requires user interaction and can affect resources beyond its original security scope, enabling limited impact to confidentiality, integrity, and availability.
Critical Impact
Successful exploitation allows script execution in a victim's browser, enabling session token theft, phishing, or unauthorized actions in the WordPress site context.
Affected Products
- Graham Quick Interest Slider WordPress plugin (quick-interest-slider)
- All versions up to and including 3.1.5
- WordPress deployments running the vulnerable plugin
Discovery Timeline
- 2025-03-27 - CVE-2025-26738 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-26738
Vulnerability Analysis
The vulnerability is a DOM-Based Cross-Site Scripting flaw in the Quick Interest Slider plugin for WordPress. DOM-Based XSS occurs when client-side JavaScript writes attacker-controlled data into the Document Object Model (DOM) without proper sanitization or encoding. The rendered page then executes injected script in the victim's browser.
Exploitation requires an authenticated user with low privileges and depends on user interaction, such as clicking a crafted link. The scope is changed, meaning the injected payload can affect components beyond the vulnerable plugin's boundary. This includes other elements of the WordPress page or session.
Root Cause
The root cause is missing or insufficient output encoding when the plugin processes user-supplied input on the client side. Data flows from an attacker-controlled source into a sink that renders HTML or executes JavaScript. Without contextual escaping, injected markup executes as script. This maps directly to [CWE-79] Improper Neutralization of Input During Web Page Generation.
Attack Vector
An attacker crafts a request or URL containing a malicious payload targeting the Quick Interest Slider plugin. The victim, typically a logged-in WordPress user, must load or interact with the crafted content. Client-side plugin code writes the payload into the DOM, triggering script execution. The attacker can then hijack sessions, redirect users, exfiltrate data visible to the browser, or perform actions on the victim's behalf within the WordPress instance. See the Patchstack XSS Vulnerability Advisory for advisory details.
Detection Methods for CVE-2025-26738
Indicators of Compromise
- Unexpected <script> tags, event handlers (onerror, onload), or javascript: URIs appearing in Quick Interest Slider content or URL parameters.
- Anomalous outbound requests from browsers to attacker-controlled domains shortly after loading pages that render the plugin.
- WordPress user sessions exhibiting unauthorized administrative actions or profile changes without corresponding legitimate activity.
Detection Strategies
- Review WordPress access logs for suspicious query strings or POST bodies targeting the plugin's endpoints with HTML or JavaScript payloads.
- Deploy a web application firewall (WAF) rule set that flags common XSS payload patterns delivered to WordPress plugin endpoints.
- Perform authenticated dynamic application security testing (DAST) against pages that render Quick Interest Slider content to identify reflected DOM sinks.
Monitoring Recommendations
- Enable Content Security Policy (CSP) reporting to capture script-source violations originating from plugin-rendered pages.
- Monitor WordPress user role changes, new administrator accounts, and plugin configuration changes correlated with suspicious HTTP requests.
- Track browser telemetry from privileged users for anomalous JavaScript execution patterns tied to the plugin's URLs.
How to Mitigate CVE-2025-26738
Immediate Actions Required
- Inventory all WordPress installations to identify sites running Quick Interest Slider version 3.1.5 or earlier.
- Deactivate the Quick Interest Slider plugin on affected sites until a patched version is confirmed and installed.
- Rotate credentials and invalidate active sessions for WordPress users who may have interacted with crafted content.
Patch Information
No fixed version is documented in the referenced advisory at the time of publication. Administrators should monitor the Patchstack XSS Vulnerability Advisory and the plugin's WordPress.org page for an updated release addressing CVE-2025-26738.
Workarounds
- Remove or disable the plugin until a vendor patch is released.
- Deploy a WAF rule that blocks HTML and JavaScript metacharacters in requests targeting Quick Interest Slider endpoints.
- Enforce a strict Content Security Policy that disallows inline scripts and restricts script sources to trusted origins.
- Restrict low-privileged accounts from accessing plugin configuration areas where the injection sink is reachable.
# Configuration example: disable the plugin via WP-CLI until patched
wp plugin deactivate quick-interest-slider
# Optional: enforce a restrictive CSP header via .htaccess
# Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
