CVE-2026-86836 in Ankaios
Summary
by MITRE • 09/14/2026
In Eclipse Ankaios versions 0.1.0 through 1.0.2, the agent creates workload files and Control Interface named pipes (FIFOs) under a predictable path derived from the agent name and a hash of the workload's runtime configuration. If a directory or FIFO already exists at that path when the agent (re)starts, the agent reuses it based only on an existence and/or file-type check, without validating its owner or permissions. A local, unprivileged user with write access to the same base directory (by default under `$TMPDIR/ankaios`, e.g. shared `/tmp`) can pre-create this path hierarchy, including the two Control Interface FIFOs, before the agent starts. The agent then treats the attacker-owned FIFOs as the legitimate Control Interface for the targeted workload. The attacker can complete the Control Interface handshake and issue requests using that workload's configured `controlInterfaceAccess` permissions, allowing impersonation of the workload and, depending on its configured permissions, unauthorized reading and/or modification of the cluster's desired state.
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Analysis
by VulDB Data Team • 09/14/2026
The vulnerability in Eclipse Ankaios versions 0.1.0 through 1.0.2 stems from a critical flaw in how the agent manages resource initialization for workloads and their associated control interfaces. The system relies on creating workload files and Control Interface named pipes, also known as FIFOs, at predictable paths derived from the agent name and a hash of the workload's runtime configuration. This deterministic path generation creates a race condition scenario where an attacker can anticipate the exact location of these resources before they are legitimately created by the Ankaios agent. The core technical flaw lies in the lack of strict ownership validation during this initialization process. When the agent starts or restarts, it checks for the existence and file type of the target path but fails to verify that the existing directory or FIFO is owned by the correct system user or possesses appropriate permissions. This oversight allows any local unprivileged user with write access to the base directory, typically located under $TMPDIR/ankaios such as a shared /tmp environment, to pre-create this hierarchy.
By exploiting this lack of validation, an attacker can create the necessary directory structure and FIFOs before the Ankaios agent initializes them for a specific workload. Once these maliciously created resources are in place, the agent mistakenly assumes they are legitimate control interfaces belonging to the targeted workload. This misidentification enables the attacker to intercept or manipulate the communication channel intended for secure management of that workload. The operational impact is severe because it allows an unprivileged user to impersonate a trusted component within the orchestration system. Through this compromised interface, the attacker can complete the Control Interface handshake and issue commands using the permissions configured in the target workload's controlInterfaceAccess settings. This effectively grants the attacker elevated privileges equivalent to those assigned to the workload they are impersonating.
The consequences of this vulnerability extend beyond simple privilege escalation within a single container or process. Depending on the specific configuration of the targeted workload, an attacker can achieve unauthorized reading and modification of the cluster's desired state. In cloud-native environments where Ankaios is deployed, the desired state represents the authoritative definition of how applications should run across the infrastructure. Unauthorized modifications to this state could lead to service disruption, data exfiltration, or further lateral movement within the network. This aligns with CWE-284 Improper Access Control and CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition, as the system checks for existence but does not securely bind ownership at the moment of use. Furthermore, this attack vector maps to MITRE ATT&CK techniques involving privilege escalation and lateral movement through inter-process communication channels that lack proper authentication or authorization checks.
To mitigate this vulnerability, it is essential to enforce strict file ownership and permission controls during resource creation. The Ankaios agent should utilize atomic operations such as O_CREAT with exclusive flags when creating FIFOs to ensure that if a path already exists, the operation fails rather than reusing an existing entity owned by another user. Additionally implementing mandatory access control policies or using secure temporary directories with restricted permissions can prevent unprivileged users from pre-creating paths in shared locations like /tmp. Upgrading to patched versions of Eclipse Ankaios where these initialization routines have been hardened is the primary remediation strategy. Administrators should also audit their deployment environments to ensure that base directories for agent data are not world-writable and restrict write access only to authorized service accounts, thereby eliminating the prerequisite condition required for this attack vector to succeed.