CVE-2025-13653 is a vulnerability classified under CWE-200 (Exposure of Sensitive Information) and CWE-863 (Incorrect Authorization) affecting floragunn's Search Guard FLX product, specifically versions from 3.1.0 up to but not including 4.0.0 when enterprise modules are disabled. Search Guard FLX is a security plugin for Elasticsearch that provides access control and encryption capabilities. The vulnerability allows an authenticated user with limited privileges to craft special requests that bypass intended access restrictions and read documents from data streams they should not have access to. This occurs because the access control mechanisms fail to properly enforce privilege checks on certain data stream read operations when enterprise modules are disabled, leading to unauthorized information disclosure. The CVSS v3.1 base score is 4.3 (medium), reflecting that the attack vector is network-based, requires low privileges, no user interaction, and impacts confidentiality only. No integrity or availability impacts are noted. No public exploits have been reported yet, but the flaw could be leveraged by insiders or compromised accounts to access sensitive data. The vulnerability was reserved on 2025-11-25 and published on 2025-12-01, indicating recent discovery. No patches or fixes are currently linked, so mitigation relies on configuration changes or awaiting vendor updates.

For European organizations, this vulnerability poses a risk of unauthorized disclosure of sensitive information stored in Elasticsearch data streams protected by Search Guard FLX. Confidentiality breaches could expose personal data, intellectual property, or other critical business information, potentially violating GDPR and other data protection regulations. The impact is heightened in sectors with stringent compliance requirements such as finance, healthcare, and government. Since exploitation requires authentication, the threat is primarily from malicious insiders or compromised user accounts. However, the ease of exploitation (low complexity) and network accessibility increase risk. Organizations relying on Search Guard FLX without enterprise modules enabled are particularly vulnerable. Data leakage incidents could lead to reputational damage, regulatory fines, and operational disruptions. The absence of integrity or availability impact limits the scope to confidentiality, but the sensitivity of exposed data could be significant.

1. Upgrade to the latest version of Search Guard FLX once a patch addressing CVE-2025-13653 is released by floragunn. 2. Temporarily enable enterprise modules if feasible, as they enforce stricter access controls preventing unauthorized data stream reads. 3. Implement strict authentication and authorization policies to minimize the number of users with access to Search Guard FLX and Elasticsearch clusters. 4. Conduct thorough audits of user privileges and remove unnecessary access rights, especially for data stream reading capabilities. 5. Employ network segmentation and firewall rules to restrict access to Elasticsearch clusters only to trusted hosts and users. 6. Monitor logs for unusual access patterns or attempts to exploit data streams. 7. Consider deploying additional data encryption at rest and in transit to reduce the impact of unauthorized reads. 8. Educate administrators and users about the risks of privilege misuse and enforce strong credential management practices.