CVE-2025-9979: Maspik WordPress Plugin Auth Bypass Flaw

CVE-2025-9979 Overview

CVE-2025-9979 affects the Maspik anti-spam plugin for WordPress in versions 2.5.6 and prior. The vulnerability stems from missing capability checks on the Maspik_spamlog_download_csv function. Authenticated users with subscriber-level access or higher can export and download the spam log database. The exported data contains blocked submission attempts, which may include misclassified legitimate submissions holding sensitive user data. The weakness is categorized under CWE-862: Missing Authorization.

Critical Impact
Any authenticated WordPress user, including low-privilege subscribers, can download spam log contents and access potentially sensitive form submission data stored by the plugin.

Affected Products

Maspik Anti-Spam plugin for WordPress (contact-forms-anti-spam)
Versions 2.5.6 and prior
WordPress sites allowing subscriber-level registration are at highest exposure

Discovery Timeline

2025-09-10 - CVE-2025-9979 published to the National Vulnerability Database
2026-06-17 - Last updated in the NVD database

Technical Details for CVE-2025-9979

Vulnerability Analysis

The Maspik plugin exposes a CSV export routine that writes the plugin's spam log to an authenticated user's browser. The export handler, Maspik_spamlog_download_csv, is reachable through standard WordPress request flows but omits the capability check that would normally restrict administrative data exports to privileged roles. As a result, any logged-in account can invoke the handler and retrieve the stored log.

The spam log contains submissions the plugin classified as unwanted. In practice this includes form fields such as names, email addresses, message bodies, IP addresses, and other content from contact and registration forms. Because anti-spam heuristics produce false positives, legitimate submissions holding sensitive information frequently end up in the same log.

The issue is scoped to confidentiality. Exploitation does not modify site data or affect availability, but it does expose user-submitted content that site operators expect to remain restricted to administrators.

Root Cause

The root cause is the absence of a current_user_can() capability check (or equivalent authorization gate) inside the CSV export function. WordPress plugins must explicitly verify that the requesting user holds a capability such as manage_options before serving administrative data. Maspik versions 2.5.6 and earlier perform only an authentication check, treating any logged-in user as authorized to invoke the export.

Attack Vector

An attacker first obtains or registers a subscriber-level account on a vulnerable WordPress site. The attacker then issues an authenticated request to the plugin endpoint that routes to Maspik_spamlog_download_csv. The server returns the CSV file containing the captured spam log without a role check. No user interaction from an administrator is required, and no additional privileges need to be escalated to retrieve the data.

Synthetic exploit code is not published here. Technical details are available in the WordPress Anti-Spam Function Code and the Wordfence Vulnerability Analysis.

Detection Methods for CVE-2025-9979

Indicators of Compromise

Unexpected HTTP requests from low-privilege accounts targeting the Maspik CSV export endpoint
CSV download responses issued to users who do not hold administrator or editor roles
Newly registered subscriber accounts that authenticate once and immediately trigger plugin admin actions
Outbound transfers of CSV content from /wp-admin/ or admin-ajax.php paths tied to the contact-forms-anti-spam plugin

Detection Strategies

Review web server access logs for requests invoking the Maspik spam log download function, especially from non-administrator session cookies
Correlate WordPress user role with HTTP response size and Content-Type: text/csv responses
Alert on subscriber-level accounts calling admin-oriented AJAX actions registered by third-party plugins

Monitoring Recommendations

Enable WordPress audit logging for file downloads and plugin administrative actions
Monitor registration spikes on sites that allow open subscriber signup
Track user-agent and IP patterns across sessions that access the Maspik export endpoint

How to Mitigate CVE-2025-9979

Immediate Actions Required

Update the Maspik anti-spam plugin to the version that patches Maspik_spamlog_download_csv with a capability check
Audit WordPress user accounts and remove unknown subscriber-level registrations
Clear the plugin's existing spam log if it contains sensitive form content that should not persist
Disable open user registration on sites that do not require it

Patch Information

The maintainer committed a fix referenced in the WordPress Anti-Spam Changeset. Site operators should upgrade to the latest release of the contact-forms-anti-spam plugin from the official WordPress plugin repository. See the Wordfence Vulnerability Analysis for version-specific guidance.

Workarounds

Deactivate the Maspik plugin until the patched release is deployed
Restrict access to WordPress admin and AJAX endpoints with a web application firewall rule that blocks requests to the vulnerable function from non-administrator sessions
Enforce the principle of least privilege by removing the subscriber role where it is not required
Require administrator approval for new account registrations

bash

# Example WordPress CLI commands to reduce exposure
wp plugin update contact-forms-anti-spam
wp option update users_can_register 0
wp user list --role=subscriber --fields=ID,user_login,user_registered