CVE-2025-54035: Newsletters Plugin CSRF Vulnerability

CVE-2025-54035 Overview

CVE-2025-54035 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the Tribulant Software Newsletters plugin (newsletters-lite) for WordPress. The flaw impacts all versions up to and including 4.10. The vulnerability is tracked under CWE-352: Cross-Site Request Forgery.

An attacker can craft a malicious web page that triggers unwanted state-changing actions in the plugin when an authenticated user visits it. Exploitation requires user interaction, but no privileges or authentication on the attacker's side. The impact is limited to integrity, with no direct confidentiality or availability consequences.

Critical Impact
Attackers can force authenticated WordPress users to perform unintended actions in the Newsletters plugin, leading to unauthorized modification of plugin data.

Affected Products

Tribulant Software Newsletters plugin (newsletters-lite) for WordPress
All versions from n/a through 4.10
WordPress sites with the affected plugin installed and activated

Discovery Timeline

2025-07-16 - CVE-2025-54035 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-54035

Vulnerability Analysis

The vulnerability stems from missing or insufficient anti-CSRF protections in the Newsletters plugin. WordPress provides nonce-based tokens to prevent forged requests, but the affected plugin endpoints do not properly validate these tokens. An attacker can construct HTML forms or JavaScript payloads on an external site that submit requests to the target WordPress instance.

When a logged-in administrator or privileged user visits the attacker's page, the browser automatically includes session cookies with the forged request. The plugin processes the request as legitimate, executing state-changing operations chosen by the attacker. The newsletters-lite plugin handles subscriber lists, campaign settings, and mailing configurations, all of which become potential targets.

The attack requires social engineering to lure a target into visiting the malicious page. Attack complexity is low, and the network attack vector allows exploitation from anywhere on the internet.

Root Cause

The root cause is the absence or improper validation of CSRF tokens on sensitive request handlers within the plugin. Handlers that modify plugin state should verify a WordPress nonce using check_admin_referer() or wp_verify_nonce(). When these checks are missing, any request bearing valid session cookies is accepted.

Attack Vector

Exploitation proceeds through a standard CSRF chain. The attacker hosts a page containing a hidden form or XMLHttpRequest targeting the vulnerable plugin endpoint. The target, already authenticated to WordPress in another browser tab, visits the malicious page. The browser sends the forged request with authentication cookies, and the plugin performs the requested action.

See the Patchstack Vulnerability Report for additional technical detail.

Detection Methods for CVE-2025-54035

Indicators of Compromise

Unexpected changes to newsletter campaigns, templates, or subscriber lists that do not correspond to legitimate administrator activity.
HTTP POST requests to Newsletters plugin endpoints with Referer headers pointing to external, untrusted domains.
Web server access logs showing plugin admin actions initiated from non-wp-admin referrers.

Detection Strategies

Audit WordPress action logs and plugin activity logs for state changes lacking a corresponding administrator login session.
Inspect HTTP request logs for missing or invalid _wpnonce parameters on Newsletters plugin admin routes.
Correlate browser session activity with plugin configuration changes to identify anomalous cross-origin request patterns.

Monitoring Recommendations

Enable a WordPress activity logging plugin to record administrative actions with source IP and referrer metadata.
Monitor outbound emails and campaign dispatches for anomalies indicating unauthorized configuration changes.
Deploy a web application firewall rule that flags requests to Newsletters admin endpoints missing valid nonce tokens.

How to Mitigate CVE-2025-54035

Immediate Actions Required

Update the Newsletters plugin to a version later than 4.10 as soon as the vendor publishes a fixed release.
Restrict WordPress administrator access to trusted networks using IP allowlisting where feasible.
Instruct administrators to log out of WordPress sessions before browsing untrusted sites.

Patch Information

At the time of NVD publication, the affected version range is listed as n/a through 4.10. Consult the Patchstack Vulnerability Report and the Tribulant Software plugin page for the latest patched release information.

Workarounds

Temporarily deactivate the newsletters-lite plugin until a patched version is installed if the plugin is not actively required.
Deploy a web application firewall with CSRF-focused rules that enforce same-origin Referer and Origin checks on WordPress admin endpoints.
Configure SameSite=Strict or SameSite=Lax cookie attributes on the WordPress session to reduce cross-site cookie transmission.

bash

# Example: WordPress hardening to reduce CSRF exposure
# Add to wp-config.php
define('COOKIE_DOMAIN', 'example.com');
define('FORCE_SSL_ADMIN', true);

# Example nginx rule to block admin POSTs without a same-origin Referer
location ~* /wp-admin/admin(-ajax|-post)\.php$ {
    if ($http_referer !~* ^https?://example\.com/) {
        return 403;
    }
}