CVE-2026-57741 Overview
CVE-2026-57741 is a stored cross-site scripting (XSS) vulnerability in the AcyMailing SMTP Newsletter plugin for WordPress. The flaw affects all versions up to and including 10.11.0. It stems from improper neutralization of user-supplied input during web page generation [CWE-79]. Attackers can inject persistent JavaScript payloads that execute in the browsers of users who view affected pages. The issue is tracked under the AcyMailing Newsletter Team's acymailing plugin and was published to the National Vulnerability Database (NVD) on July 13, 2026.
Critical Impact
Successful exploitation allows attackers to store malicious scripts that execute against site visitors and administrators, enabling session theft, credential harvesting, and administrative account takeover through a scope-changing payload.
Affected Products
- AcyMailing SMTP Newsletter plugin for WordPress
- All versions from n/a through 10.11.0
- WordPress sites running the vulnerable acymailing plugin
Discovery Timeline
- 2026-07-13 - CVE-2026-57741 published to NVD
- 2026-07-13 - Last updated in NVD database
Technical Details for CVE-2026-57741
Vulnerability Analysis
The vulnerability is a stored XSS flaw in the AcyMailing SMTP Newsletter plugin. The plugin fails to properly sanitize or encode user-controlled input before rendering it in web pages generated by the application. Because the payload is persisted server-side, every subsequent page load that renders the affected data triggers execution of the injected script in the victim's browser.
The attack requires user interaction, meaning the victim must load or view the affected page. Exploitation crosses a trust boundary, allowing scripts injected in one context to affect resources in a different security scope. Successful exploitation can lead to session hijacking, arbitrary actions performed as the authenticated user, defacement, and phishing against site administrators.
Root Cause
The root cause is missing or insufficient output encoding of untrusted input during web page generation, classified under [CWE-79]. Input reaches an HTML rendering context without contextual escaping, allowing an attacker-controlled string to be interpreted as executable script by the browser.
Attack Vector
The vulnerability is exploitable over the network without authentication. An attacker submits a crafted payload to an input field processed by the AcyMailing plugin. The payload is stored by the application and rendered later to any user viewing the affected view. When an administrator loads the page, the script executes in the administrator's session context, enabling account takeover paths.
No verified public exploit code is available at the time of publication. See the Patchstack Vulnerability Report for advisory details.
Detection Methods for CVE-2026-57741
Indicators of Compromise
- Newsletter or subscriber records containing <script>, onerror=, onload=, or javascript: substrings in stored fields.
- Unexpected outbound requests from administrator browsers to external domains shortly after loading AcyMailing admin pages.
- WordPress user accounts created or elevated to administrator without corresponding admin action in audit logs.
Detection Strategies
- Inspect the WordPress database tables associated with the acymailing plugin for HTML or JavaScript syntax in text fields.
- Enable and review web application firewall (WAF) logs for POST requests to AcyMailing endpoints containing script tags or event-handler attributes.
- Monitor browser Content Security Policy (CSP) violation reports for inline script executions on wp-admin pages.
Monitoring Recommendations
- Alert on modifications to WordPress wp_users and wp_usermeta tables originating from browser sessions rather than CLI or scheduled tasks.
- Track file integrity of plugin directories under wp-content/plugins/acymailing/ for unexpected changes.
- Correlate administrator login events with immediate requests to unfamiliar external hosts.
How to Mitigate CVE-2026-57741
Immediate Actions Required
- Update the AcyMailing SMTP Newsletter plugin to a version later than 10.11.0 as soon as the vendor publishes a fixed release.
- Audit all stored newsletter, subscriber, and template records for injected HTML or JavaScript and remove malicious content.
- Rotate credentials and session tokens for any WordPress administrator who accessed affected pages during the exposure window.
Patch Information
Refer to the Patchstack Vulnerability Report for the current fixed version and vendor advisory. Apply the update through the WordPress plugin manager or via automated update tooling.
Workarounds
- Disable the AcyMailing SMTP Newsletter plugin until a patched version is installed if updates cannot be applied immediately.
- Restrict access to AcyMailing administrative endpoints using IP allowlists at the web server or WAF layer.
- Deploy a strict Content Security Policy that blocks inline scripts and unauthorized external script sources on wp-admin pages.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
