CVE-2024-56223: Gulri Slider XSS Vulnerability

CVE-2024-56223 Overview

CVE-2024-56223 is a reflected cross-site scripting (XSS) vulnerability in the Gulri Slider WordPress plugin developed by Fahad Mahmood. The flaw stems from improper neutralization of user-supplied input during web page generation [CWE-79]. Affected versions include Gulri Slider up to and including 3.5.8. An attacker can craft a malicious URL that, when followed by an authenticated or unauthenticated victim, executes arbitrary JavaScript in the victim's browser session. The vulnerability scope changes, meaning injected scripts can affect components beyond the originally vulnerable plugin context.

Critical Impact

Successful exploitation enables session hijacking, credential theft, defacement, and redirection of WordPress site visitors and administrators.

Affected Products

• Fahad Mahmood Gulri Slider plugin for WordPress
• All versions from n/a through 3.5.8
• WordPress sites with the gulri-slider plugin installed and active

Discovery Timeline

• 2024-12-31 - CVE-2024-56223 published to the National Vulnerability Database (NVD)
• 2026-06-17 - Last updated in the NVD database

Technical Details for CVE-2024-56223

Vulnerability Analysis

The Gulri Slider plugin fails to properly sanitize and escape user-controllable input before rendering it within HTML responses. When the plugin reflects request parameters into the page output without contextual encoding, an attacker can inject arbitrary HTML and JavaScript. The injected payload executes in the browser of any user who visits the crafted URL. Because the vulnerability is reflected rather than stored, exploitation requires user interaction, typically through phishing or social engineering. The changed scope in the CVSS vector indicates the injected content can affect resources beyond the vulnerable component, such as parent WordPress pages or other plugins sharing the document origin.

Root Cause

The root cause is missing or insufficient output encoding in the plugin's request handlers. Input parameters arriving via HTTP GET or POST requests are concatenated into the HTML response without escaping characters such as <, >, ", and '. WordPress provides helper functions including esc_html(), esc_attr(), and wp_kses() for safe output, but the plugin does not consistently apply them in the affected code paths up to version 3.5.8.

Attack Vector

An attacker constructs a URL that includes a malicious JavaScript payload within a vulnerable request parameter consumed by the Gulri Slider plugin. The attacker delivers this URL through email, social media, or a malicious site. When the victim clicks the link, the WordPress server reflects the payload into the rendered page, and the browser executes it under the site's origin. The attacker can then exfiltrate cookies, perform actions on behalf of the victim, or pivot to administrative functions if the victim holds elevated privileges. Refer to the Patchstack Vulnerability Report for additional technical context.

Detection Methods for CVE-2024-56223

Indicators of Compromise

• HTTP request logs containing URL parameters with encoded <script>, javascript:, or onerror= sequences targeting gulri-slider endpoints
• Outbound browser requests to attacker-controlled domains originating shortly after a user visits a WordPress site with the plugin installed
• Unexpected administrative actions, password resets, or new user creations following an authenticated administrator clicking an external link

Detection Strategies

• Inspect web server access logs for query strings containing HTML special characters or known XSS payload patterns directed at plugin URLs
• Deploy a web application firewall (WAF) rule set with signatures for reflected XSS and monitor blocked requests targeting WordPress plugin paths
• Use content security policy (CSP) violation reports to identify inline script execution attempts on pages rendered by the plugin

Monitoring Recommendations

• Enable verbose logging on WordPress installations and forward access logs to a centralized SIEM for correlation
• Track plugin version inventory across managed WordPress sites and alert when gulri-slider versions at or below 3.5.8 are detected
• Monitor for anomalous session activity, including session token reuse from new IP addresses immediately after a link click event

How to Mitigate CVE-2024-56223

Immediate Actions Required

• Identify all WordPress installations running the Gulri Slider plugin and confirm the installed version
• Deactivate the gulri-slider plugin until a patched release is verified and installed
• Rotate session cookies and force re-authentication for administrative accounts that may have visited untrusted links

Patch Information

As of the last NVD update on 2026-06-17, no fixed version is identified in the published advisory. The vulnerability affects all versions up to and including 3.5.8. Site administrators should consult the Patchstack Vulnerability Report for updates on patched releases and apply them as soon as they are made available by the plugin author.

Workarounds

• Remove or deactivate the Gulri Slider plugin until a fixed version is released
• Deploy a WAF rule that blocks requests containing script tags or JavaScript URI schemes in parameters bound to plugin endpoints
• Implement a strict Content Security Policy that disallows inline script execution and restricts script sources to trusted origins
• Educate administrators and editors to avoid clicking unsolicited links pointing to their own WordPress sites

# Configuration example: Apache mod_security rule to block reflected XSS payloads targeting the plugin
SecRule REQUEST_URI "@contains /wp-content/plugins/gulri-slider/" \
  "chain,id:1056223,phase:2,deny,status:403,msg:'Block suspected XSS targeting gulri-slider (CVE-2024-56223)'"
  SecRule ARGS "@rx (?i)(<script|javascript:|onerror=|onload=)" "t:none,t:urlDecodeUni"