CVE-2025-3870 is a vulnerability identified in the '1 Decembrie 1918' WordPress plugin developed by olarmarius. This plugin is affected in all versions up to and including version 1.dec.2012. The vulnerability is classified as Cross-Site Scripting (XSS) under CWE-79, specifically caused by improper neutralization of input during web page generation. The root cause is the absence or incorrect implementation of nonce validation on the plugin's main PHP page (1-decembrie-1918/1-decembrie-1918.php). Nonces are security tokens used in WordPress to verify that requests originate from legitimate sources and prevent Cross-Site Request Forgery (CSRF). Due to missing or faulty nonce checks, an unauthenticated attacker can craft a malicious request that, if an authenticated site administrator is tricked into clicking (e.g., via a phishing link), allows the attacker to update plugin settings and inject malicious scripts into the website. This injection can lead to the execution of arbitrary JavaScript in the context of the administrator's browser session, potentially compromising session tokens, redirecting users, or performing unauthorized actions. Although no known exploits are currently in the wild, the vulnerability's nature means it can be exploited remotely without authentication, relying on social engineering to induce administrator interaction. The plugin's widespread use in WordPress sites that focus on Romanian historical content or related themes increases the attack surface. The vulnerability was reserved and published in April 2025, with enrichment from CISA, but no official patch or CVSS score has been provided yet.

For European organizations, particularly those operating WordPress sites with the '1 Decembrie 1918' plugin, this vulnerability poses a significant risk to website integrity and administrative control. Successful exploitation can lead to unauthorized changes in site configuration, injection of malicious scripts, and potential compromise of administrator credentials or session cookies. This can result in defacement, data leakage, or pivoting to further attacks within the organization's network. Given the plugin's cultural and historical focus, institutions such as museums, cultural organizations, educational entities, and media outlets in Romania and neighboring countries may be primary targets. The impact extends beyond confidentiality to integrity and availability, as attackers could disrupt website operations or use compromised sites to distribute malware or conduct phishing campaigns. The reliance on social engineering to trigger the exploit means that organizations with less stringent user awareness training or lax administrative controls are more vulnerable. Additionally, the lack of a patch increases the window of exposure, potentially inviting opportunistic attackers to develop exploits.

1. Immediate audit of all WordPress installations to identify the presence of the '1 Decembrie 1918' plugin, especially versions up to 1.dec.2012. 2. Disable or remove the plugin until an official patch is released. 3. Implement strict administrative policies to limit plugin installation and updates to trusted personnel only. 4. Enhance administrator user training focused on recognizing phishing attempts and suspicious links to reduce the risk of social engineering exploitation. 5. Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious POST requests targeting the vulnerable plugin's PHP page. 6. Monitor web server logs for unusual requests or patterns indicative of exploitation attempts. 7. If immediate patching is not possible, consider applying manual nonce validation or input sanitization as a temporary mitigation, if technically feasible. 8. Regularly back up website data and configurations to enable quick restoration in case of compromise. 9. Stay updated with vendor announcements and subscribe to threat intelligence feeds for timely patch releases or exploit disclosures.