CVE-2025-24000 is a high-severity authentication bypass vulnerability (CWE-288) found in the WPExperts Post SMTP plugin, affecting versions up to 3.2.0. This vulnerability allows an attacker with low privileges (PR:L) to bypass authentication mechanisms by exploiting an alternate path or communication channel within the plugin. The vulnerability is remotely exploitable over the network (AV:N) without requiring user interaction (UI:N). The CVSS v3.1 base score is 8.8, indicating a significant risk with high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). The Post SMTP plugin is commonly used in WordPress environments to manage SMTP email sending, which is critical for website functionality such as user notifications, password resets, and transactional emails. By bypassing authentication, an attacker could gain unauthorized access to plugin functionalities or potentially escalate privileges, manipulate email configurations, intercept or alter email content, or disrupt email delivery. Although no known exploits are currently reported in the wild, the vulnerability's characteristics suggest it could be leveraged for impactful attacks if weaponized. The lack of a published patch at the time of this report increases the urgency for mitigation and monitoring. The vulnerability was reserved in January 2025 and published in August 2025, indicating recent discovery and disclosure.

For European organizations, this vulnerability poses a significant threat, especially those relying on WordPress websites with the Post SMTP plugin for critical communications. Successful exploitation could lead to unauthorized access to email configurations, enabling attackers to intercept sensitive communications, conduct phishing campaigns, or disrupt business operations by disabling email notifications. This could compromise personal data under GDPR, leading to regulatory penalties and reputational damage. Organizations in sectors such as finance, healthcare, e-commerce, and government are particularly at risk due to the sensitive nature of their communications. Additionally, the ability to alter email content or delivery could facilitate further attacks like credential theft or malware distribution. The high impact on confidentiality, integrity, and availability underscores the potential for widespread operational disruption and data breaches within European enterprises.

Given the absence of an official patch, European organizations should implement immediate compensating controls. These include restricting access to WordPress admin interfaces and the Post SMTP plugin to trusted IP addresses via firewall rules or VPNs, enforcing strong multi-factor authentication for all administrative accounts, and monitoring logs for unusual access patterns or configuration changes. Organizations should also consider temporarily disabling the Post SMTP plugin if feasible or replacing it with alternative secure SMTP plugins that have no known vulnerabilities. Regularly updating WordPress core and all plugins remains critical to minimize exposure. Network-level protections such as Web Application Firewalls (WAFs) should be configured to detect and block suspicious requests targeting the plugin. Additionally, organizations should prepare incident response plans to quickly address any exploitation attempts and conduct security awareness training to mitigate phishing risks that could be facilitated by this vulnerability.