CVE-2026-48786 in Fleet
Summary
by MITRE • 08/26/2026
Fleet is an open-source device management platform built on osquery. In versions prior to 4.87.0, the target search endpoint (POST /api/latest/fleet/targets) returned unmasked team enroll secrets and full team configuration, including credential-bearing agent options, to low-privilege observer-class users. Other team-facing endpoints mask these fields for observers, but the target search endpoint did not apply the same sanitization, so an authenticated user with the Observer, Observer+, or Technician role, whether global or team-scoped, could retrieve the secrets and agent options by performing a target search against an observer-runnable query. With a leaked team enroll secret an attacker could enroll unauthorized hosts into the affected team, and if the team's agent options contained credentials such as AWS secret access keys or proxy passwords, those values were disclosed as well. This issue is fixed in version 4.87.0.
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Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified in Fleet versions prior to 4.87.0 represents a critical information disclosure flaw stemming from inconsistent data sanitization logic within the application's API layer. Fleet, an open-source device management platform built on osquery, relies heavily on strict role-based access control to manage sensitive configuration data across distributed teams. The core technical failure lies in the target search endpoint located at POST /api/latest/fleet/targets. While other team-facing endpoints correctly masked sensitive fields such as enroll secrets and credential-bearing agent options for users with lower privileges, this specific endpoint failed to apply the same sanitization filters. This inconsistency allowed authenticated users possessing Observer, Observer+, or Technician roles, whether scoped globally or to a specific team, to bypass security controls by performing target searches against queries that are permitted for observer-level execution.
From an operational perspective, the impact of this vulnerability is severe due to the nature of the data exposed. The endpoint returned unmasked team enroll secrets and full team configurations directly in the response payload. Team enroll secrets serve as cryptographic keys required to register new devices with a specific Fleet server instance. Consequently, any user who could access these secrets gained the ability to enroll unauthorized hosts into the affected team's infrastructure. This action effectively grants the attacker control over additional endpoints within the organization's network, potentially expanding their attack surface and allowing for lateral movement or further data exfiltration depending on the permissions of those newly enrolled devices.
Furthermore, the vulnerability extended beyond mere enrollment capabilities by exposing credential-bearing agent options embedded in the team configuration. These configurations often contain sensitive authentication tokens such as AWS secret access keys, proxy passwords, or other API credentials required for osquery agents to function correctly within enterprise environments. The disclosure of these values provides an attacker with direct access to external cloud services and internal network proxies associated with the compromised team's infrastructure. This level of exposure can lead to significant data breaches, unauthorized resource consumption in cloud environments, and potential manipulation of system configurations across the managed fleet.
This flaw aligns closely with CWE-200: Information Exposure, specifically falling under categories related to sensitive information leakage through API endpoints due to improper access control or sanitization failures. In terms of offensive security frameworks, this vulnerability facilitates initial foothold establishment and privilege escalation within the device management ecosystem, mapping to MITRE ATT&CK techniques such as T1539: Steal Web Session Cookie if session tokens were also exposed, but more accurately reflecting T1078: Valid Accounts when considering the unauthorized enrollment of hosts using stolen credentials. The attacker leverages valid low-privilege accounts to extract high-value secrets, effectively escalating their influence over the infrastructure without needing higher-level administrative privileges initially.
The resolution for this issue was implemented in version 4.87.0 by ensuring that all team-facing endpoints, including the target search endpoint, apply consistent sanitization logic regardless of user role or query type. Organizations running affected versions must upgrade immediately to mitigate the risk of unauthorized device enrollment and credential leakage. Additionally, it is recommended to rotate any enroll secrets and exposed credentials for teams where this vulnerability was active during its existence, as prior exposure may have already compromised those assets. Regular auditing of API endpoint behaviors against role-based access control policies can help prevent similar inconsistencies in future development cycles.