Description

Missing Authorization (CWE-862) in the Elasticsearch custom inference service can lead to information disclosure via Privilege Abuse (CAPEC-122). A user holding only inference execution privileges could cause outbound inference traffic to be directed to a destination of their choosing and could cause administrator-provisioned credentials to be exposed.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.4",
  "pubDate": "2026-09-01T20:17:24.030Z",
  "pubdate": "2026-09-01T20:17:24.030Z",
  "executiveSummary": "A critical Missing Authorization vulnerability (CWE-862) has been identified within the Elasticsearch custom inference service. This flaw allows an authenticated user, assigned only the minimum privilege level required for inference execution, to perform unauthorized actions beyond their intended scope.\nThe vulnerability manifests as a breakdown in access control, enabling the redirection of outbound inference traffic to attacker-controlled destinations. Furthermore, this privilege abuse (CAPEC-122) facilitates the exfiltration of sensitive administrator-provisioned credentials. The risk implications are severe, as the vulnerability potentially exposes internal service secrets and permits arbitrary network communication under the guise of the Elasticsearch service.\nSuccessful exploitation requires the attacker to possess legitimate, albeit restricted, inference execution privileges within the Elasticsearch environment. By manipulating the parameters of the inference request, a user can circumvent the intended security boundaries of the custom inference service. This vulnerability poses a significant threat to organizational data confidentiality and infrastructure integrity, necessitating immediate attention to access control configurations and service security policies.",
  "technicalDetails": "The vulnerability stems from an improper authorization check within the custom inference service of Elasticsearch (CWE-862). The underlying root cause is the failure of the service to validate the destination parameters of inference requests against an allowed-list or to enforce mandatory access control (MAC) policies when processing service-specific metadata.\nUnder normal operations, the inference service is intended to communicate with predefined, administrator-configured endpoints using pre-provisioned credentials. However, due to the identified authorization flaw, the application layer does not strictly verify the authorization context when a user submits an inference request. This allows an attacker to manipulate the request payload, specifically targeting the outbound destination parameters to redirect traffic to an external, attacker-controlled infrastructure.\nThe attack flow proceeds as follows: First, an attacker authenticates to the Elasticsearch cluster with standard inference execution privileges. Second, the attacker crafts a malicious inference request. While the request appears standard, it includes modified destination attributes designed to override the default service behavior. Third, the custom inference service, failing to restrict these parameters, initiates an outbound connection to the specified malicious URI. Fourth, as part of the established communication protocol, the service may inadvertently inject administrator-provisioned credentials (such as API keys or secret tokens) into the header or payload of the outbound request. Finally, the attacker captures this traffic on the receiving end, effectively harvesting the sensitive credentials and potentially leveraging them to escalate privileges or move laterally within the environment.\nThis vulnerability constitutes a form of Server-Side Request Forgery (SSRF) facilitated by privilege abuse (CAPEC-122), where the internal inference service acts as a proxy for the attacker. The vulnerable component is the custom inference module responsible for handling third-party model interaction. Because the service is inherently trusted to handle sensitive configuration data, the exposure of credentials occurs silently, circumventing perimeter defenses. The impact is not limited to the service itself but extends to the broader infrastructure managed by the leaked administrative credentials, potentially leading to full cluster compromise."
}