CVE-2026-84173 in Ankaios
Summary
by MITRE • 09/07/2026
In Eclipse Ankaios versions v0.5.1 through v1.0.1, the agent-side Control Interface authorizer incorrectly evaluates multi-segment allow rules whose first path segment is a wildcard. An authenticated workload with access restricted by such a rule can submit a CompleteStateRequest or UpdateStateRequest with an empty field mask. The request may then be incorrectly authorized as matching the scoped rule, allowing the workload to read the complete cluster state or replace state outside its authorized subtree. This may result in unauthorized disclosure or modification of other workloads and cluster configuration. Only a rule consisting solely of * is intended to authorize an empty mask.
Mitigation: Until an update containing the fix is installed, avoid multi-segment Control Interface allow-rule filter masks that begin with a wildcard, such as *.workloads.some_workload. Replace them with explicit paths such as desiredState.workloads.some_workload, where applicable. A filter mask consisting solely of * has different, intentionally unrestricted semantics and should only be used when full-state access is intended.
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Analysis
by VulDB Data Team • 09/07/2026
The vulnerability in Eclipse Ankaios versions v0.5.1 through v1.0.1 represents a critical authorization bypass within the agent-side Control Interface authorizer. This flaw specifically affects multi-segment allow rules where the first path segment utilizes a wildcard character, such as .workloads.some_workload. The core technical deficiency lies in how the system evaluates these complex filter masks against incoming requests that contain an empty field mask. In standard authorization logic, an empty field mask typically implies no specific fields are being targeted or modified, which should restrict access to only those resources explicitly permitted by a rule designed for broad state retrieval, such as one consisting solely of . However, the flawed implementation incorrectly interprets an empty field mask submitted via CompleteStateRequest or UpdateStateRequest operations as matching these multi-segment wildcard rules. This misinterpretation allows authenticated workloads that are supposed to be restricted to specific subsets of the cluster state to bypass those restrictions entirely.
The operational impact of this vulnerability is severe, leading directly to unauthorized disclosure and modification of sensitive system data. Because the authorizer incorrectly grants access based on the flawed rule evaluation, an attacker or compromised workload can submit requests with empty field masks that are erroneously authorized under scoped rules intended for narrower permissions. This enables the actor to read the complete cluster state rather than just their designated portion, resulting in a significant confidentiality breach where sensitive configuration details and operational data of other workloads become visible. Furthermore, if the vulnerability is exploited through an UpdateStateRequest, it allows the workload to replace or modify state outside its authorized subtree. This integrity violation can lead to destabilization of the cluster, unauthorized changes to critical configurations, and potential cascading failures across dependent services that rely on accurate state management.
This issue aligns with CWE-269, Improper Privilege Management, as it involves a failure in enforcing access control policies for an authenticated user or process. It also maps closely to ATT&CK technique T1078, Valid Accounts, since the exploitation requires authentication but abuses legitimate credentials to gain unauthorized privileges beyond their assigned scope. The root cause is not a lack of authentication but rather a logical error in the authorization engine that fails to distinguish between broad unrestricted access and scoped partial access when dealing with wildcard prefixes. This distinction is crucial for maintaining the principle of least privilege within container orchestration environments, where workloads must be isolated from one another's state data unless explicitly permitted otherwise.
To mitigate this risk until a patched version is deployed, administrators should immediately audit their Control Interface allow-rule configurations. Any multi-segment filter masks that begin with a wildcard, such as .workloads.some_workload, should be replaced with explicit path definitions like desiredState.workloads.some_workload where applicable. This change ensures that the authorization logic correctly binds permissions to specific state paths rather than relying on ambiguous wildcard prefixes that trigger the vulnerability. It is also critical to distinguish these scoped rules from filter masks consisting solely of , which have different semantics intended for full-state access and should only be used when unrestricted read or write capabilities are genuinely required by a workload. By tightening rule definitions, organizations can restore proper isolation between workloads and prevent unauthorized state manipulation or disclosure within the Ankaios cluster environment.