CVE-2025-28957: OwnerRez API Stored XSS Vulnerability

CVE-2025-28957 Overview

CVE-2025-28957 is a stored Cross-Site Scripting (XSS) vulnerability affecting the OwnerRez API WordPress plugin through version 1.2.1. The flaw stems from improper neutralization of user-supplied input during web page generation, categorized under [CWE-79]. An authenticated attacker with low privileges can inject malicious scripts that persist in the application and execute in the browser of any user who views the affected page. The scope change indicated in the CVSS vector means the injected payload can impact resources beyond the vulnerable component itself.

Critical Impact
Authenticated attackers can inject persistent JavaScript payloads that execute in visitor and administrator browsers, enabling session theft, credential harvesting, or unauthorized actions within the WordPress environment.

Affected Products

OwnerRez API WordPress plugin versions up to and including 1.2.1
WordPress installations using the OwnerRez integration for vacation rental management
Sites where the plugin is active and reachable by authenticated low-privilege users

Discovery Timeline

2025-07-04 - CVE-2025-28957 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-28957

Vulnerability Analysis

The OwnerRez API plugin fails to sanitize or encode user-controlled input before rendering it within generated HTML. This allows an attacker to submit crafted input containing JavaScript that the plugin stores and later reflects into a page as executable script. Because the payload is stored server-side, it executes whenever a victim loads the affected view. The vulnerability requires authentication with low privileges and user interaction to trigger the payload against another user. The changed scope indicates that a successful injection can affect components outside the plugin's security boundary, such as the broader WordPress administrative interface.

Root Cause

The root cause is missing or insufficient output encoding of input values that flow into HTML contexts. The plugin trusts input submitted through its interface and writes it into the DOM without applying WordPress escaping functions such as esc_html(), esc_attr(), or wp_kses(). Any HTML control characters, including <script> tags or event handler attributes, pass through unchanged.

Attack Vector

An attacker with a low-privileged authenticated account submits a crafted payload through an input field processed by the OwnerRez plugin. The payload persists in plugin storage. When an administrator or other user navigates to the page rendering that data, the injected script executes with the victim's session context. Typical outcomes include session cookie theft, forced administrative actions through CSRF-style requests, and injection of secondary payloads into the site. See the Patchstack XSS Vulnerability Report for the technical writeup.

Detection Methods for CVE-2025-28957

Indicators of Compromise

Unexpected <script>, <iframe>, or on* event handler attributes stored in plugin-managed database tables or post metadata
Outbound requests from administrator browsers to unfamiliar domains shortly after loading OwnerRez plugin pages
New or modified WordPress administrator accounts created without a corresponding admin action in audit logs

Detection Strategies

Inspect plugin-managed database entries for HTML control characters and JavaScript syntax in fields expected to contain plain text
Review web server access logs for POST requests to OwnerRez plugin endpoints carrying script payloads or URL-encoded HTML tags
Deploy a Web Application Firewall (WAF) rule set that flags XSS patterns targeting WordPress plugin endpoints

Monitoring Recommendations

Enable WordPress audit logging to capture content changes made by low-privileged accounts
Monitor Content Security Policy (CSP) violation reports for inline script executions on plugin-rendered pages
Alert on privilege changes or new admin session creations that follow visits to OwnerRez plugin views

How to Mitigate CVE-2025-28957

Immediate Actions Required

Update the OwnerRez API plugin to a version later than 1.2.1 once the vendor releases a patched build
Audit existing plugin data for stored payloads and remove any entries containing script or event handler content
Restrict plugin access to trusted authenticated users and review recently created accounts

Patch Information

At the time of publication, the advisory lists versions up to and including 1.2.1 as affected. Refer to the Patchstack advisory for updated fix availability and apply the latest release from the WordPress plugin repository as soon as it is published.

Workarounds

Deactivate the OwnerRez API plugin until a patched version is available if the integration is not business-critical
Deploy a WAF rule that blocks requests containing HTML tags or JavaScript keywords to OwnerRez plugin endpoints
Enforce a strict Content Security Policy that disallows inline scripts on WordPress administrative pages

bash

# Example CSP header to reduce XSS execution risk in nginx
add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'self'" always;