CVE-2026-73080 in SeaweedFS
Summary
by MITRE • 08/11/2026
SeaweedFS is a distributed storage system. Prior to 4.24, VolumeServer.FetchAndWriteNeedle in weed/server/volume_grpc_remote.go fetches a caller-supplied remote endpoint through weed/remote_storage/s3/s3_storage_client.go and writes the response into a needle. The RPC performs no authentication and no target validation, allowing anyone who can reach a volume server's gRPC port to cause requests to arbitrary hosts, including loopback, link-local, RFC 1918, and cloud metadata endpoints such as 169.254.169.254, and read the response. On cloud deployments, this can disclose instance metadata and IAM credentials and reach otherwise unexposed internal services. The volume server gRPC plane is unauthenticated by default, and configuring documented JWT signing keys does not protect this RPC. This issue is fixed in version 4.24.
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Analysis
by VulDB Data Team • 08/11/2026
SeaweedFS represents a distributed storage system that has been identified with a critical security vulnerability affecting versions prior to 4.24. The vulnerability resides within the VolumeServer.FetchAndWriteNeedle functionality located in weed/server/volume_grpc_remote.go, which processes remote endpoint requests through the weed/remote_storage/s3/s3_storage_client.go component. This flaw creates an unauthorized access vector where any individual capable of reaching the volume server's gRPC port can initiate requests to arbitrary network destinations without proper authentication or target validation mechanisms.
The technical implementation of this vulnerability demonstrates a fundamental failure in input validation and access control within the gRPC RPC interface. The system accepts caller-supplied remote endpoints directly without implementing any form of endpoint sanitization or authorization checks, creating an unrestricted proxy scenario where malicious actors can traverse network boundaries to reach internal services that should remain protected. This design flaw enables attackers to target loopback addresses, link-local networks, private RFC 1918 address ranges, and cloud metadata endpoints such as the well-known 169.254.169.254 address used by cloud platforms for instance metadata services.
The operational impact of this vulnerability extends significantly in cloud deployment environments where it can result in unauthorized disclosure of sensitive information including instance metadata, IAM credentials, and access tokens that could provide attackers with elevated privileges and persistent access to cloud resources. This issue represents a classic case of insecure direct object reference vulnerability where the system fails to properly validate or authenticate remote endpoint requests before processing them. The vulnerability affects the gRPC communication plane which operates unauthenticated by default, meaning that even when administrators attempt to secure the system using documented JWT signing keys, these protections do not extend to this specific RPC interface, leaving it exposed to exploitation.
The security implications align with CWE-284 (Improper Access Control) and CWE-918 (Server-Side Request Forgery) classifications, demonstrating how inadequate input validation can create pathways for attackers to bypass normal network segmentation and access internal services. From an attacker perspective, this vulnerability maps to ATT&CK technique T1566.002 (Phishing: Spearphishing Attachment) and T1071.004 (Application Layer Protocol: DNS) where adversaries can leverage the system's trust in remote endpoints to gain unauthorized access to sensitive data. Organizations deploying SeaweedFS in cloud environments face significant risk of credential theft, privilege escalation, and lateral movement within their infrastructure, making this vulnerability particularly dangerous for multi-tenant or public cloud deployments where isolation between services is critical.
The remediation approach requires upgrading to version 4.24 or later where the vulnerability has been addressed through proper authentication implementation and endpoint validation controls. Security teams should also consider implementing network segmentation, firewall rules, and monitoring of gRPC traffic to detect potential exploitation attempts. Additionally, organizations should review their deployment configurations to ensure that default unauthenticated RPC interfaces are not exposed to untrusted networks and that proper access controls have been implemented across all communication channels within their distributed storage infrastructure.
This vulnerability serves as a critical reminder of the importance of input validation and authentication in distributed systems where remote endpoints are processed. The flaw demonstrates how seemingly simple functionality can create significant security risks when proper access controls and validation mechanisms are omitted from the implementation, particularly in systems that serve as foundational components for data storage and retrieval operations within enterprise environments.