CVE-2025-5257 is a medium-severity vulnerability in Mautic, an open-source marketing automation platform widely used for managing marketing campaigns and customer engagement. The vulnerability arises from improper validation of access permissions on unpublished page previews. Specifically, the preview functionality for pages that are not yet published is accessible via predictable URLs (e.g., /page/preview/1, /page/preview/2) without requiring any authentication or authorization checks. This flaw allows any unauthenticated user, including automated search engine crawlers, to access draft content that was intended to remain private until publication. Consequently, sensitive or confidential marketing content, campaign strategies, or other unpublished information could be inadvertently exposed to the public or indexed by search engines, leading to potential information leakage. The vulnerability is classified under CWE-1284 (Improper Validation of Specified Quantity in Input), indicating a failure to properly validate input parameters that control access to resources. The CVSS v3.1 base score is 6.5, reflecting a network attack vector with low attack complexity, no privileges or user interaction required, and limited confidentiality and availability impacts. The integrity of content is not affected. Mautic has addressed this issue by implementing proper permission checks on preview pages, ensuring that only authorized users can access unpublished content previews. Users of Mautic versions greater than 4.0 are advised to upgrade to the patched version to mitigate this vulnerability.

For European organizations using Mautic for marketing automation, this vulnerability poses a risk of unintended disclosure of sensitive or strategic marketing content. Exposure of unpublished campaign materials could lead to competitive disadvantages, reputational damage, or leakage of confidential business information. Additionally, if sensitive personal data or proprietary information is included in draft pages, this could raise compliance concerns under the GDPR, potentially resulting in regulatory scrutiny or fines. The indexing of draft content by search engines exacerbates the risk by making sensitive information publicly searchable and persistent. Although the vulnerability does not allow modification of content or system compromise, the confidentiality breach and partial availability impact (due to exposure of content not intended for public access) are significant. Organizations relying on Mautic for customer engagement and marketing should consider the reputational and operational impacts of such data leakage, especially in sectors with high confidentiality requirements such as finance, healthcare, and government.

To mitigate this vulnerability, European organizations should immediately upgrade Mautic installations to the latest patched version that enforces proper authorization checks on unpublished page previews. Beyond patching, organizations should audit their Mautic configurations to ensure that preview URLs are not publicly accessible and that access controls are properly configured. Implementing web application firewalls (WAFs) with rules to restrict access to preview endpoints can provide an additional layer of defense. Organizations should also review their robots.txt and meta tags to prevent search engines from indexing sensitive preview URLs, although this is not a substitute for proper access control. Regular security assessments and penetration testing focusing on access control mechanisms in marketing platforms are recommended. Finally, organizations should train marketing and IT teams on secure content management practices to avoid accidental exposure of sensitive draft content.