CVE-2025-15018 is a critical authorization bypass vulnerability in the Optional Email plugin for WordPress, maintained by djanym. The vulnerability arises because the plugin's 'random_password' filter, which influences password reset key generation, is not properly scoped to registration contexts. This oversight allows unauthenticated attackers to specify a known password reset key during the password reset process. Consequently, an attacker can initiate a password reset for any user account, including administrators, by setting a predictable reset key, then use this key to reset the password and gain full access to the account. The vulnerability affects all versions up to and including 1.3.11. The CVSS 3.1 score of 9.8 reflects the vulnerability's high impact: it requires no privileges or user interaction, can be exploited remotely over the network, and compromises confidentiality, integrity, and availability. The flaw is categorized under CWE-639 (Authorization Bypass Through User-Controlled Key), highlighting improper authorization checks. No patches or fixes are currently linked, and no known exploits have been reported in the wild, but the vulnerability's nature suggests it could be weaponized quickly. This vulnerability is particularly dangerous for WordPress sites relying on this plugin for email functionality, as it undermines the password reset security mechanism, a critical component of user account protection.

For European organizations, the impact of CVE-2025-15018 is significant. WordPress is widely used across Europe for websites ranging from small businesses to large enterprises and government portals. Organizations using the Optional Email plugin are at risk of unauthorized account takeover, including administrative accounts, which could lead to full site compromise. This can result in data breaches, defacement, insertion of malicious content, or use of the compromised site as a launchpad for further attacks. The breach of administrator accounts can also lead to loss of control over sensitive information and disruption of services, impacting business continuity and reputation. Given the critical nature of the vulnerability and the ease of exploitation, attackers could rapidly compromise multiple sites, especially those with weak monitoring or delayed patching processes. The impact extends beyond individual sites to potentially affect supply chains and customer trust, particularly in sectors with stringent data protection regulations such as GDPR. The lack of known exploits in the wild suggests a window for proactive mitigation, but the high severity demands urgent attention.

1. Immediate action should be to update the Optional Email plugin to a patched version once available. Until a patch is released, consider disabling the plugin to eliminate the attack surface. 2. Implement web application firewall (WAF) rules to detect and block suspicious password reset requests that include unusual or user-controlled reset keys. 3. Monitor logs for abnormal password reset activity, especially multiple resets initiated from the same IP or targeting administrative accounts. 4. Enforce multi-factor authentication (MFA) on all administrative accounts to reduce the risk of account takeover even if passwords are reset. 5. Restrict password reset functionality to verified users by adding additional verification steps such as CAPTCHA or email confirmation links that cannot be bypassed. 6. Conduct an audit of user accounts to identify any unauthorized password changes and enforce password resets for all users after mitigation. 7. Educate site administrators about this vulnerability and encourage rapid response to suspicious activity. 8. Consider isolating critical WordPress instances or limiting plugin usage to reduce exposure. 9. Regularly back up site data and configurations to enable recovery in case of compromise. 10. Engage with the plugin vendor or community to track patch releases and vulnerability disclosures.