CVE-2025-31011: SimplyRETS Real Estate IDX XSS Vulnerability

CVE-2025-31011 Overview

CVE-2025-31011 is a reflected Cross-Site Scripting (XSS) vulnerability in the ReichertBrothers SimplyRETS Real Estate IDX WordPress plugin (simply-rets). The flaw stems from improper neutralization of user-supplied input during web page generation [CWE-79]. All plugin versions from initial release through 3.2.2 are affected. An attacker can craft a malicious URL that, when clicked by a victim, executes arbitrary JavaScript in the victim's browser session against the WordPress site. The scope is changed, meaning injected scripts can affect resources beyond the vulnerable component. Successful exploitation can lead to session hijacking, credential theft, or redirection to attacker-controlled infrastructure.

Critical Impact

Attackers can execute arbitrary JavaScript in a victim's browser by tricking them into clicking a crafted link, enabling session theft and unauthorized actions on the WordPress site.

Affected Products

• ReichertBrothers SimplyRETS Real Estate IDX plugin for WordPress
• All versions from initial release through 3.2.2
• WordPress sites using the simply-rets plugin for MLS/IDX listings

Discovery Timeline

• 2025-04-15 - CVE-2025-31011 published to the National Vulnerability Database (NVD)
• 2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-31011

Vulnerability Analysis

The vulnerability is a reflected XSS issue in the SimplyRETS Real Estate IDX plugin. User-controlled input passed to the plugin is reflected back into the rendered HTML response without proper output encoding or sanitization. An attacker constructs a URL containing a JavaScript payload in a vulnerable parameter and delivers it to a victim through phishing, social engineering, or a malicious referrer. When the victim loads the URL, the payload executes in the context of the WordPress site's origin.

Because the CVSS scope is changed, the injected script can reach resources beyond the plugin itself, including authenticated WordPress sessions. The vulnerability requires user interaction but no privileges or prior authentication, broadening the pool of viable targets to any visitor who can be enticed to click a link.

Root Cause

The root cause is missing or insufficient input neutralization in a code path that echoes request parameters into the response body. The plugin fails to apply WordPress sanitization helpers such as esc_html(), esc_attr(), or wp_kses() before emitting user-supplied values into HTML contexts.

Attack Vector

The attack is network-based and requires the victim to interact with a crafted link. A typical exploitation flow involves an attacker hosting or distributing a URL pointing to a vulnerable plugin endpoint with a JavaScript payload embedded in a query parameter. Once executed, the payload can read DOM content, exfiltrate cookies that lack the HttpOnly flag, submit authenticated requests on the user's behalf, or stage further client-side attacks.

The vulnerability is described in prose only; no public proof-of-concept code is included in this advisory. Consult the Patchstack Vulnerability Report for additional technical context.

Detection Methods for CVE-2025-31011

Indicators of Compromise

• HTTP request logs containing URL parameters with <script>, javascript:, onerror=, or onload= patterns directed at simply-rets plugin endpoints
• Unexpected outbound requests from end-user browsers to attacker-controlled domains following a visit to a WordPress site running the plugin
• WordPress access logs showing repeated requests with encoded payloads (%3Cscript%3E, %22%3E%3C) targeting plugin query strings

Detection Strategies

• Inspect web server and WordPress access logs for query string anomalies referencing simply-rets paths or shortcodes
• Deploy a Web Application Firewall (WAF) with OWASP Core Rule Set signatures for reflected XSS patterns
• Monitor Content Security Policy (CSP) violation reports for inline script execution attempts on pages rendered by the plugin

Monitoring Recommendations

• Centralize WordPress and reverse proxy logs in a SIEM and alert on XSS heuristics targeting plugin endpoints
• Track plugin version inventory across hosted WordPress sites to identify instances running simply-rets at or below 3.2.2
• Review referrer headers for suspicious external domains directing traffic to plugin URLs with non-standard parameters

How to Mitigate CVE-2025-31011

Immediate Actions Required

• Update the SimplyRETS Real Estate IDX plugin to a version newer than 3.2.2 once the vendor publishes a fixed release
• Audit all WordPress installations for the simply-rets plugin and confirm the running version
• Educate site administrators and editors about phishing links that may target authenticated sessions

Patch Information

The affected version range covers all releases up to and including 3.2.2. Site operators should monitor the Patchstack Vulnerability Report and the official plugin repository for a fixed release and apply it as soon as it is available.

Workarounds

• Deploy a WAF rule that blocks requests containing script tags or event-handler attributes targeting simply-rets endpoints
• Disable or remove the plugin until a patched version is released if the IDX functionality is not business-critical
• Enforce a strict Content Security Policy that disallows inline scripts and restricts script sources to trusted origins

# Example WAF/ModSecurity rule to block reflected XSS attempts against the plugin
SecRule REQUEST_URI "@contains simply-rets" \
  "chain,phase:2,deny,status:403,id:1031011,msg:'Block XSS attempt against simply-rets'"
SecRule ARGS "@rx (?i)(<script|javascript:|onerror=|onload=)" "t:none,t:urlDecodeUni"