CVE-2024-51718 Overview
CVE-2024-51718 is a reflected Cross-Site Scripting (XSS) vulnerability affecting the Simple Modal WordPress plugin by arsdehnel. The flaw exists in all versions up to and including 0.3.3. The plugin fails to properly neutralize user-supplied input during web page generation, allowing attackers to inject arbitrary JavaScript that executes in a victim's browser context. Exploitation requires user interaction, typically through a crafted link. Successful attacks can lead to session hijacking, credential theft, and unauthorized actions performed with the victim's privileges within the WordPress environment.
Critical Impact
Attackers can execute arbitrary JavaScript in the browser of any user who clicks a maliciously crafted link, potentially compromising WordPress administrator sessions and site integrity.
Affected Products
- arsdehnel Simple Modal WordPress plugin (simplemodal)
- All versions from n/a through <= 0.3.3
- WordPress installations using the vulnerable plugin
Discovery Timeline
- 2024-11-09 - CVE-2024-51718 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-51718
Vulnerability Analysis
The vulnerability is classified under [CWE-79], improper neutralization of input during web page generation. The Simple Modal plugin reflects user-controlled input into HTTP responses without applying adequate output encoding or input sanitization. When a victim requests a URL containing an attacker-supplied payload, the plugin renders that payload directly within the HTML response.
The attack proceeds over the network without authentication. However, it requires user interaction, meaning a victim must be enticed to click a crafted link or visit an attacker-controlled page. Because the scope changes upon successful exploitation, injected scripts can access resources beyond the immediate vulnerable component, including cookies and session tokens of the WordPress site.
The EPSS probability for exploitation is 0.259% at the 17.222 percentile, indicating limited observed exploitation activity. No public proof-of-concept exploit is currently listed, and the vulnerability is not present on the CISA Known Exploited Vulnerabilities catalog.
Root Cause
The root cause is missing or insufficient sanitization of request parameters before they are echoed back into the rendered HTML. The plugin does not apply WordPress functions such as esc_html(), esc_attr(), or wp_kses() to untrusted input before output. As a result, HTML and JavaScript syntax supplied by an attacker is interpreted by the browser rather than treated as inert text.
Attack Vector
An attacker crafts a URL targeting a page rendered by the vulnerable Simple Modal plugin. The URL includes a JavaScript payload in a reflected parameter. When a WordPress user, particularly a logged-in administrator, follows the link, the payload executes in their browser under the origin of the WordPress site. The attacker can then exfiltrate session cookies, perform authenticated administrative actions, deface content, or pivot to further attacks against site users.
See the Patchstack WordPress Plugin Vulnerability advisory for additional technical detail.
Detection Methods for CVE-2024-51718
Indicators of Compromise
- HTTP request logs containing script tags, event handlers, or JavaScript URIs in query parameters directed at Simple Modal endpoints
- Unexpected outbound requests from browser sessions to attacker-controlled domains following clicks on WordPress-hosted links
- WordPress administrative actions originating from unusual IP addresses or occurring shortly after suspicious referral traffic
Detection Strategies
- Inspect web server access logs for URL parameters containing encoded payloads such as %3Cscript%3E, onerror=, or javascript: targeting the Simple Modal plugin path
- Deploy web application firewall (WAF) rules that detect reflected XSS patterns in query strings and POST bodies
- Correlate WordPress audit logs with reverse proxy logs to identify session activity following anomalous request patterns
Monitoring Recommendations
- Enable verbose logging on the WordPress instance and reverse proxy to capture full request URIs and referrer headers
- Monitor for administrator account activity following external link clicks, particularly session token reuse from new IP addresses
- Track plugin file integrity and configuration changes that could indicate post-exploitation persistence
How to Mitigate CVE-2024-51718
Immediate Actions Required
- Identify all WordPress installations running the Simple Modal plugin at version 0.3.3 or earlier
- Deactivate and remove the plugin until a patched release is confirmed available
- Rotate WordPress administrator credentials and invalidate active sessions if exploitation is suspected
Patch Information
At the time of publication, no fixed version is listed by the vendor. The advisory indicates the vulnerability affects all versions through <= 0.3.3. Consult the Patchstack advisory for the latest fix status and vendor communications.
Workarounds
- Remove or disable the Simple Modal plugin until a vendor-supplied patch is available
- Deploy a WAF with reflected XSS protection rules in front of the WordPress site
- Enforce a strict Content Security Policy (CSP) that disallows inline scripts and restricts script sources to trusted origins
- Require administrators to use separate browsers or profiles for WordPress management to reduce cross-context exposure
# Example CSP header to mitigate reflected XSS impact
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'self'"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
