CVE-2026-54746 in hatchet
Summary
by MITRE • 08/28/2026
Hatchet is a platform for orchestrating background tasks, AI agents, and durable workflows at scale. From 0.40.0 until 0.91.1, the Dispatcher gRPC service does not verify that a request's worker ID belongs to the tenant identified by the bearer-token context in Dispatcher/UpsertWorkerLabels and Dispatcher/Unsubscribe. An authenticated owner of any tenant who guesses another tenant's worker UUID can overwrite that worker's affinity labels or disconnect the worker from the dispatcher. This can cause cross-tenant integrity impact and denial of service on multi-tenant Hatchet Cloud or shared self-hosted deployments. Single-tenant deployments are not practically affected because the attacker and target tenant are the same. This issue is fixed in version 0.91.1.
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Analysis
by VulDB Data Team • 08/28/2026
The vulnerability identified within the Hatchet platform, specifically affecting versions from 0.40.0 through 0.91.1, represents a critical failure in access control logic for its Dispatcher gRPC service. Hatchet is designed to orchestrate background tasks, AI agents, and durable workflows at scale, often operating in multi-tenant environments where strict isolation between tenants is paramount for security and operational integrity. The core technical flaw lies in the insufficient validation of worker identifiers during specific administrative operations. When a client invokes either the Dispatcher/UpsertWorkerLabels or Dispatcher/Unsubscribe endpoints, the service relies on the bearer token present in the request context to identify the requesting tenant but fails to verify that the target worker ID provided in the request payload actually belongs to that same tenant. This architectural oversight allows an authenticated user who possesses valid credentials for one tenant to manipulate workers associated with a different tenant, provided they can guess or otherwise obtain the correct UUID of the target worker.
This lack of cross-tenant authorization checks leads directly to significant integrity and availability impacts in multi-tenant deployments such as Hatchet Cloud or shared self-hosted instances. An attacker exploiting this flaw could overwrite the affinity labels of another tenant's workers, potentially disrupting task routing logic and causing workloads to be assigned incorrectly or lost entirely. Furthermore, by invoking the unsubscribe function with a guessed worker UUID from an external tenant, an adversary can forcibly disconnect those workers from the dispatcher service. This action effectively halts the execution of background tasks and workflows belonging to the victim tenant, resulting in a denial of service that disrupts business operations dependent on these asynchronous processes. The severity is amplified by the fact that many distributed systems rely on predictable or sequential UUID generation patterns, making it feasible for attackers to enumerate valid worker identifiers through brute-force techniques if proper randomization is not enforced at the identifier generation layer.
The risk profile changes significantly in single-tenant deployments where only one tenant exists within a given instance of Hatchet. In such scenarios, any authenticated user interacting with the system inherently belongs to the same tenant as all existing workers. Consequently, while the technical flaw remains present, it does not facilitate cross-tenant attacks because there is no distinct external tenant boundary to violate. The attacker and target are effectively the same entity from a logical perspective, meaning that even if an operator guesses another worker's UUID within their own organization, they would only be affecting resources under their own administrative control. Therefore, this vulnerability is primarily a concern for multi-tenant architectures where isolation guarantees must be strictly enforced to prevent lateral movement or cross-account disruption.
From a standards classification perspective, this issue aligns with CWE-284, which describes Improper Access Control, specifically highlighting the failure to enforce proper restrictions on authorized individuals accessing specific resources. It also relates closely to CWE-639, Injection of Critical Data into an External System via Untrusted Input, as the worker ID is treated as unvalidated external input that influences system state without sufficient verification against the authenticated context. In terms of offensive security frameworks such as MITRE ATT&CK, this vulnerability facilitates techniques associated with Privilege Escalation and Defense Evasion by allowing a lower-privileged or distinct tenant actor to interfere with higher-priority operational components belonging to another entity. It also touches upon Impact categories related to Denial of Service via resource exhaustion or disruption of service availability mechanisms.
To mitigate this risk, organizations running affected versions must upgrade immediately to version 0.91.1 or later, where the Dispatcher gRPC service has been patched to enforce strict ownership verification for worker-related operations. Until an upgrade is feasible, administrators should implement network-level access controls to restrict exposure of the gRPC endpoints to only trusted internal subnets and ensure that API gateways perform rigorous validation of tenant context against resource identifiers before forwarding requests to the backend services. Additionally, employing UUIDs with high entropy or randomization can reduce the feasibility of guessing valid worker IDs, thereby adding a layer of defense-in-depth against enumeration-based attacks targeting this specific access control flaw.