CVE-2025-24617 Overview
CVE-2025-24617 is a reflected Cross-Site Scripting (XSS) vulnerability in the AcyMailing SMTP Newsletter plugin for WordPress. The flaw stems from improper neutralization of user-supplied input during web page generation [CWE-79]. Attackers can inject arbitrary JavaScript into responses returned by the plugin, executing code in the victim's browser within the WordPress site context.
The vulnerability affects all AcyMailing SMTP Newsletter versions up to and including 9.11.1. Exploitation requires user interaction, typically through a crafted link that delivers the malicious payload. Successful attacks can lead to session hijacking, credential theft, and unauthorized administrative actions.
Critical Impact
Reflected XSS enables attackers to execute arbitrary JavaScript in administrator browsers, potentially leading to account takeover and full WordPress site compromise via a single crafted link.
Affected Products
- AcyMailing SMTP Newsletter plugin for WordPress
- All versions up to and including 9.11.1
- WordPress sites with AcyMailing installed and active
Discovery Timeline
- 2025-02-14 - CVE CVE-2025-24617 published to NVD
- 2026-04-23 - Last updated in NVD database
Technical Details for CVE-2025-24617
Vulnerability Analysis
The AcyMailing SMTP Newsletter plugin fails to properly sanitize and encode user-controlled input before reflecting it back in HTTP responses. This classic reflected XSS pattern allows attackers to embed JavaScript payloads in request parameters that the plugin echoes into the rendered HTML.
When a victim clicks a crafted link containing the payload, the browser parses the injected script as legitimate page content. The script then executes with the privileges of the targeted user session. Administrator-level victims expose the entire WordPress installation to compromise.
The vulnerability requires user interaction but no authentication. Attackers can deliver malicious links through phishing emails, malicious websites, or social media. The scope-changed CVSS classification reflects that exploitation impacts components beyond the vulnerable plugin itself.
Root Cause
The root cause is insufficient output encoding of reflected request data. The plugin renders user input into HTML responses without applying context-appropriate escaping such as esc_html(), esc_attr(), or wp_kses(). This allows raw HTML and JavaScript syntax to be interpreted by the browser rather than displayed as text.
Attack Vector
The attack vector is network-based and requires victim interaction. An attacker crafts a URL targeting a vulnerable AcyMailing endpoint, embedding a JavaScript payload in a vulnerable parameter. The attacker delivers this URL through phishing or social engineering. When an authenticated WordPress user, particularly an administrator, clicks the link, the payload executes in their browser session.
The vulnerability mechanism follows the standard reflected XSS pattern. See the Patchstack AcyMailing XSS Vulnerability advisory for additional technical details.
Detection Methods for CVE-2025-24617
Indicators of Compromise
- HTTP requests to AcyMailing plugin endpoints containing <script>, javascript:, or onerror= patterns in query parameters
- URL-encoded payload variants such as %3Cscript%3E or %6Aavascript in referrer logs
- Unexpected outbound requests from administrator browser sessions to attacker-controlled domains
- Anomalous WordPress administrative actions originating from legitimate admin accounts shortly after clicking external links
Detection Strategies
- Inspect web server access logs for AcyMailing plugin URLs containing HTML or JavaScript syntax in parameters
- Deploy Web Application Firewall (WAF) rules matching common XSS payload signatures targeting AcyMailing endpoints
- Monitor WordPress audit logs for administrative changes that follow suspicious referrer patterns
- Correlate browser-based telemetry with WordPress session activity to identify post-click anomalies
Monitoring Recommendations
- Enable verbose logging on the WordPress installation, including plugin request parameters
- Forward web server and WordPress logs to a centralized SIEM for correlation and alerting
- Track AcyMailing plugin version inventory across all managed WordPress sites
- Alert on new administrator account creation or privilege changes following external link clicks
How to Mitigate CVE-2025-24617
Immediate Actions Required
- Identify all WordPress sites running AcyMailing SMTP Newsletter version 9.11.1 or earlier
- Update the plugin to a version newer than 9.11.1 that addresses this vulnerability
- Force password resets and invalidate active sessions for WordPress administrators if compromise is suspected
- Review recent administrative actions and plugin installations for unauthorized changes
Patch Information
Update the AcyMailing SMTP Newsletter plugin to a version higher than 9.11.1. Refer to the Patchstack AcyMailing XSS Vulnerability advisory for vendor patch details and the fixed version reference.
Workarounds
- Deploy a Web Application Firewall with rules blocking XSS payloads targeting AcyMailing endpoints
- Temporarily deactivate the AcyMailing plugin if patching cannot be performed immediately
- Enforce Content Security Policy (CSP) headers restricting inline script execution on the WordPress site
- Train administrators to avoid clicking unsolicited links pointing to their own WordPress installation
# Example Content Security Policy header to limit XSS impact
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.
