CVE-2025-47288 is a vulnerability identified in the discourse-policy plugin for the Discourse platform, specifically affecting versions prior to 0.1.1. The discourse-policy plugin is designed to enable administrators to confirm that users have acknowledged or completed certain actions or policies. The vulnerability arises when a policy is posted in a public topic but is associated with a private group. Due to improper access control, members of the private group could be inadvertently exposed to non-group members, leading to unauthorized disclosure of group membership information. This is classified under CWE-200, which concerns the exposure of sensitive information to unauthorized actors. The vulnerability does not allow modification or deletion of data, nor does it affect system availability, but it compromises confidentiality by leaking private group membership details. The CVSS v3.1 base score is 3.5, indicating a low severity level. The vector indicates that the attack requires network access (AV:N), low attack complexity (AC:L), privileges (PR:L), and user interaction (UI:R). The scope is unchanged (S:U), and the impact is limited to confidentiality (C:L), with no impact on integrity or availability. There are no known exploits in the wild, and the issue has been patched in version 0.1.1. A recommended workaround before patching is to move any policy topics linked to private groups into restricted categories to prevent public exposure.

For European organizations using Discourse with the discourse-policy plugin, this vulnerability could lead to unintended exposure of private group memberships to unauthorized users. While the direct impact is limited to confidentiality and is considered low severity, the exposure of group membership can have reputational consequences, especially if the groups are related to sensitive projects, internal investigations, or confidential collaborations. In regulated industries such as finance, healthcare, or government sectors within Europe, unauthorized disclosure of group membership could potentially violate data protection regulations like GDPR if it leads to personal data exposure. Furthermore, adversaries could leverage this information for social engineering or targeted attacks. However, since exploitation requires some level of privileges and user interaction, the risk is somewhat mitigated. Organizations relying on Discourse for internal communications or community management should be aware of this risk and act accordingly.

The primary mitigation is to upgrade the discourse-policy plugin to version 0.1.1 or later, where the vulnerability is patched. Until the patch can be applied, administrators should move any policy topics associated with private groups into restricted categories that are not publicly accessible, effectively preventing unauthorized users from viewing sensitive group membership information. Additionally, organizations should audit their Discourse instance configurations to ensure that private groups and their associated policies are not inadvertently exposed in public forums. Implementing strict access controls and regularly reviewing group memberships and topic visibility settings can further reduce the risk. Monitoring user activity and logs for unusual access patterns related to policy topics can help detect attempted exploitation. Finally, educating users about the importance of cautious interaction with policy topics can reduce the likelihood of successful exploitation requiring user interaction.