CVE-2025-67819 is a security vulnerability identified in Weaviate OSS, an open-source vector search engine, affecting versions before 1.33.4. The root cause is a lack of proper validation on the fileName parameter within the GetFile method of the FileReplicationService. This service is responsible for replicating files between shards in a distributed Weaviate deployment. The vulnerability manifests when a shard is in the "Pause file activity" state, a condition likely used to temporarily halt file operations during maintenance or replication. During this state, an attacker who can invoke the GetFile method and reach the FileReplicationService can supply crafted fileName inputs to read arbitrary files accessible by the service process. This means the attacker can potentially access sensitive files on the host system, leading to unauthorized disclosure of confidential data. Exploitation does not require user interaction but does require the attacker to have network access to the FileReplicationService endpoint and the ability to call GetFile. No authentication bypass is explicitly mentioned, but the lack of validation on fileName is the critical flaw. No public exploits or CVSS scores are currently available, but the vulnerability is significant due to the potential for sensitive data exposure and the relative ease of exploitation in certain deployment scenarios. The issue was publicly disclosed on December 12, 2025, and fixed in Weaviate OSS version 1.33.4. Organizations running affected versions should upgrade promptly. The vulnerability highlights the importance of input validation and secure service state management in distributed systems.

For European organizations, the impact of CVE-2025-67819 can be substantial, especially for those using Weaviate OSS in environments handling sensitive or regulated data such as personal information, intellectual property, or financial records. Unauthorized file access could lead to data breaches, violating GDPR and other data protection regulations, resulting in legal penalties and reputational damage. The ability to read arbitrary files could expose configuration files, credentials, or other sensitive artifacts, potentially facilitating further attacks. The impact is heightened in multi-tenant or cloud environments where Weaviate is used as a service, as attackers might access data belonging to other tenants. Additionally, organizations in sectors like finance, healthcare, and government are particularly vulnerable due to the critical nature of their data. The lack of authentication bypass details suggests that network-level controls and service exposure are key risk factors. Therefore, the threat primarily affects confidentiality but could indirectly impact integrity and availability if attackers leverage exposed data for further compromise.

To mitigate CVE-2025-67819, European organizations should immediately upgrade Weaviate OSS to version 1.33.4 or later where the vulnerability is patched. Until patching is possible, restrict network access to the FileReplicationService endpoint using firewalls or network segmentation to limit exposure to trusted hosts only. Implement strong authentication and authorization controls on the service endpoints to prevent unauthorized invocation of the GetFile method. Monitor logs for unusual file access patterns or repeated calls to GetFile during shard pause states. Employ host-based intrusion detection systems to detect anomalous file read activities. Review and harden the configuration of Weaviate deployments to minimize the attack surface, including disabling unnecessary services or features. Conduct regular security assessments and penetration testing focusing on inter-shard communication and file replication mechanisms. Finally, educate DevOps and security teams about the importance of validating input parameters and managing service states securely in distributed systems.