CVE-2026-0829: WordPress File Manager Info Disclosure Flaw

CVE-2026-0829 Overview

The Frontend File Manager Plugin for WordPress through version 23.5 contains a Missing Authorization vulnerability (CWE-862) that allows unauthenticated users to abuse the site's email functionality and access uploaded files without permission. The vulnerability enables attackers to use affected WordPress sites as open relays for spam or phishing campaigns, while also exposing sensitive information through predictable file ID enumeration.

Critical Impact

Attackers can exploit vulnerable WordPress sites as email relays for malicious campaigns and gain unauthorized access to uploaded files containing potentially sensitive information.

Affected Products

• Frontend File Manager Plugin for WordPress through version 23.5

Discovery Timeline

• 2026-02-17 - CVE CVE-2026-0829 published to NVD
• 2026-02-18 - Last updated in NVD database

Technical Details for CVE-2026-0829

Vulnerability Analysis

This vulnerability stems from a Missing Authorization flaw (CWE-862) in the Frontend File Manager Plugin for WordPress. The plugin fails to implement proper authentication and authorization checks on critical functionality, creating two distinct attack surfaces.

First, the email functionality within the plugin lacks any security verification, allowing unauthenticated remote attackers to send emails through the WordPress site. This effectively transforms the site into an open mail relay that can be exploited for spam distribution or targeted phishing attacks. The abuse of legitimate WordPress infrastructure makes these malicious emails more likely to bypass spam filters and appear trustworthy to recipients.

Second, the plugin uses predictable file IDs for uploaded content without verifying user authorization. Attackers can enumerate these file IDs through sequential guessing, gaining access to files uploaded by other users. This can lead to exposure of confidential documents, personal information, or proprietary business data depending on how the file manager is used.

Root Cause

The root cause of this vulnerability is the absence of authentication and authorization checks in the plugin's email sending and file access functions. The plugin does not verify whether requests originate from authenticated users with appropriate permissions before processing email transmission or file retrieval operations. This is a classic example of CWE-862 (Missing Authorization), where security-critical functionality is exposed without proper access controls.

Attack Vector

The attack vector is network-based and requires no authentication or user interaction. An attacker can exploit this vulnerability by sending crafted HTTP requests directly to the vulnerable WordPress endpoints. For email abuse, the attacker submits requests to the email functionality specifying arbitrary recipient addresses and message content. For file access, the attacker iterates through numeric file IDs until valid files are discovered and downloaded.

The vulnerability can be exploited by sending specially crafted requests to the plugin's email and file sharing endpoints. Attackers can abuse the email functionality by submitting unauthenticated POST requests with arbitrary recipient addresses and message content. For file enumeration, attackers can iterate through sequential file IDs to discover and access uploaded content without authorization. Technical details are available in the WPScan Vulnerability Report.

Detection Methods for CVE-2026-0829

Indicators of Compromise

• Unusual outbound email volume originating from the WordPress server or associated mail services
• Web server logs showing sequential or enumeration-style requests to file download endpoints with varying file IDs
• Spike in email queue activity or mail delivery failures from the WordPress installation
• Access logs revealing requests to Frontend File Manager endpoints from unknown or suspicious IP addresses

Detection Strategies

• Monitor web application firewall (WAF) logs for repeated unauthenticated requests to file manager plugin endpoints
• Implement rate limiting and anomaly detection on email sending functions within WordPress
• Review WordPress application logs for patterns indicating file ID enumeration attempts
• Configure SIEM rules to alert on unusual email relay activity originating from web server infrastructure

Monitoring Recommendations

• Enable detailed logging for the Frontend File Manager Plugin and associated WordPress email functions
• Monitor outbound SMTP connections and email volumes for anomalies that could indicate relay abuse
• Set up alerts for high-frequency requests to plugin-specific URL patterns from single IP addresses
• Regularly audit file access logs to identify unauthorized downloads or suspicious access patterns

How to Mitigate CVE-2026-0829

Immediate Actions Required

• Update the Frontend File Manager Plugin to the latest version that addresses this vulnerability
• Temporarily disable the Frontend File Manager Plugin if an update is not immediately available
• Implement WAF rules to block unauthenticated access to the plugin's email and file sharing endpoints
• Review server email logs for signs of abuse and take remediation steps if relay activity is detected

Patch Information

Administrators should check for available updates to the Frontend File Manager Plugin and apply the latest security patches. Monitor the WPScan Vulnerability Report for updated remediation guidance and patch availability information.

Workarounds

• Restrict access to the Frontend File Manager Plugin functionality to authenticated users only through WordPress configuration or server-level access controls
• Implement rate limiting on the web server to prevent enumeration attacks against file IDs
• Configure outbound email restrictions to limit the volume and frequency of emails that can be sent through WordPress
• Use a security plugin to add authentication requirements to vulnerable endpoints until an official patch is available

# Example .htaccess rule to restrict access to file manager endpoints
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{REQUEST_URI} ^/wp-content/plugins/frontend-file-manager/ [NC]
    RewriteCond %{HTTP_COOKIE} !wordpress_logged_in [NC]
    RewriteRule .* - [F,L]
</IfModule>