CVE-2025-3870: 1 Decembrie 1918 WordPress CSRF Vulnerability

CVE-2025-3870 Overview

CVE-2025-3870 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the 1 Decembrie 1918 plugin for WordPress in all versions up to and including 1.dec.2012. The flaw resides in the 1-decembrie-1918/1-decembrie-1918.php page, which lacks proper nonce validation. Unauthenticated attackers can update plugin settings and inject malicious web scripts by tricking an authenticated administrator into clicking a crafted link. Successful exploitation results in stored Cross-Site Scripting (XSS) in the administrator context [CWE-79].

Critical Impact
Attackers can inject persistent JavaScript into WordPress sites by coercing an administrator to visit a malicious URL, enabling session theft, defacement, and further site compromise.

Affected Products

1 Decembrie 1918 WordPress plugin — all versions through 1.dec.2012
WordPress sites with the plugin installed and active
Administrator accounts targeted through social engineering

Discovery Timeline

2025-04-25 - CVE-2025-3870 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-3870

Vulnerability Analysis

The 1 Decembrie 1918 plugin exposes a settings handler in 1-decembrie-1918.php that processes state-changing requests without verifying a WordPress nonce token. WordPress provides wp_nonce_field() and check_admin_referer() primitives specifically to bind form submissions to an authenticated user session. Because the plugin omits these checks, any request reaching the handler with valid admin cookies is accepted as legitimate.

An attacker crafts an HTML page or link that submits a forged request to the vulnerable endpoint. When a logged-in administrator visits the attacker-controlled resource, the browser attaches the WordPress session cookie and the request executes with administrator privileges. The forged submission writes attacker-controlled data into plugin settings, which the plugin later renders without sufficient output encoding, producing stored XSS.

Root Cause

The root cause is missing or incorrect nonce validation on the plugin's settings page. WordPress's nonce mechanism is the standard defense against CSRF, and its absence allows cross-origin state changes. The secondary defect is insufficient sanitization of stored settings values, which converts the CSRF into a stored script injection.

Attack Vector

Exploitation requires user interaction from a site administrator, such as clicking a link or loading a page hosting the forged request. The attacker does not need credentials or an existing session on the target site. Attack complexity is low because the exploit requires only a single HTTP request forged against a known endpoint. The scope changes because injected scripts execute in the WordPress admin origin, affecting components beyond the vulnerable plugin.

No public proof-of-concept exploit is listed for this CVE. Technical details are available in the Wordfence Vulnerability Report and the WordPress Plugin Source Code.

Detection Methods for CVE-2025-3870

Indicators of Compromise

Unexpected modifications to 1 Decembrie 1918 plugin settings in the wp_options table
Presence of <script>, onerror, or onload attributes in stored plugin configuration values
Outbound HTTP requests from administrator browsers to unfamiliar domains after visiting third-party links
New or unfamiliar administrator accounts created shortly after a plugin settings change

Detection Strategies

Monitor WordPress access logs for POST requests to 1-decembrie-1918/1-decembrie-1918.php originating from external Referer headers
Review the wp_options table for plugin option values containing HTML or JavaScript payloads
Alert on administrator sessions performing settings updates immediately after navigating from an external domain

Monitoring Recommendations

Enable WordPress audit logging to capture option updates with the acting user, timestamp, and source IP
Deploy a Web Application Firewall (WAF) rule to inspect POST bodies to the plugin endpoint for script content
Correlate administrator authentication events with subsequent configuration changes to surface CSRF-driven activity

How to Mitigate CVE-2025-3870

Immediate Actions Required

Deactivate and remove the 1 Decembrie 1918 plugin until a patched version is available
Audit plugin settings for injected script content and reset affected options to safe defaults
Force logout of all administrator sessions and require credential rotation
Instruct administrators to avoid clicking untrusted links while authenticated to WordPress

Patch Information

No patched version is listed at the time of publication. All versions up to and including 1.dec.2012 are affected. Monitor the WordPress Plugin Information page for updates from the plugin author.

Workarounds

Remove the plugin from production sites until a fix is released by the maintainer
Restrict administrator access to the WordPress dashboard using IP allowlisting at the web server or WAF layer
Deploy a browser isolation policy for administrator accounts to reduce CSRF exposure from arbitrary browsing
Add a WAF rule that blocks POST requests to the plugin path when the Referer header is missing or off-origin

bash

# Example WAF rule (ModSecurity) blocking off-origin POSTs to the vulnerable endpoint
SecRule REQUEST_METHOD "@streq POST" \
  "chain,id:1002025387,phase:2,deny,status:403,msg:'CVE-2025-3870 CSRF block'"
  SecRule REQUEST_URI "@contains /1-decembrie-1918/1-decembrie-1918.php" \
    "chain"
    SecRule &REQUEST_HEADERS:Referer "@eq 0"