The vulnerability identified as CVE-2025-10638 affects the NS Maintenance Mode for WP WordPress plugin versions up to 1.3.1. It is classified under CWE-862, indicating missing authorization controls. Specifically, the subscriber export function within the plugin lacks proper authorization checks, allowing any unauthenticated attacker to remotely access and download a list of subscribers containing personally identifiable information such as names and email addresses. The CVSS 3.1 base score is 5.3 (medium), reflecting that the attack vector is network-based (AV:N), requires no privileges (PR:N), no user interaction (UI:N), and impacts confidentiality only (C:L), without affecting integrity or availability. The vulnerability does not require authentication, making it trivial for attackers to exploit. Although no public exploits are known yet, the exposure of subscriber data can facilitate further attacks like phishing or spam campaigns. The plugin is commonly used in WordPress sites to manage maintenance mode, often on sites with subscriber-based content or newsletters. The lack of a patch at the time of reporting necessitates immediate mitigation steps by administrators. The vulnerability's impact is limited to data confidentiality breaches, but the sensitivity of subscriber information makes it a significant privacy concern.

For European organizations, this vulnerability poses a risk of unauthorized disclosure of subscriber data, which can lead to privacy violations under regulations such as GDPR. The leakage of names and email addresses can facilitate targeted phishing, spear-phishing, and spam campaigns, potentially leading to further compromise or reputational damage. Organizations relying on WordPress sites with subscriber lists for marketing, communications, or membership management are particularly vulnerable. Although the vulnerability does not affect site availability or integrity, the breach of subscriber confidentiality can undermine user trust and result in regulatory penalties. The impact is more pronounced for entities handling large subscriber bases or sensitive subscriber data. Additionally, the exposure of subscriber information can be leveraged by threat actors for social engineering attacks against the organization or its users.

Administrators should immediately review the usage of the NS Maintenance Mode for WP plugin and disable or restrict the subscriber export functionality until a security patch is released. Access to maintenance mode features should be limited to authenticated and authorized users only, ideally through role-based access controls or IP whitelisting. Monitoring web server logs for unusual access patterns to the export endpoint can help detect exploitation attempts. If possible, temporarily uninstalling or replacing the plugin with a more secure alternative is advisable. Organizations should also ensure that subscriber data is minimized and encrypted where feasible. Regular audits of WordPress plugins for security updates and vulnerabilities should be part of the security hygiene. Finally, informing subscribers about potential data exposure and advising caution against phishing attempts can mitigate downstream risks.