CVE-2026-13057 in Server
Summary
by MITRE • 07/22/2026
An issue in the server’s Atlas Search integration allows an authenticated user to bypass per-user access controls.
In sharded topologies, the $search and $searchMeta aggregation stages use internal routing that is normally populated only by the trusted router during sharded search planning. Due to insufficient input validation, an authenticated client can supply these fields directly.
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Analysis
by VulDB Data Team • 07/22/2026
This vulnerability resides within MongoDB's Atlas Search functionality and represents a critical access control bypass issue affecting sharded database deployments. The flaw exists in how the system handles internal routing information during aggregation operations involving $search and $searchMeta stages. When MongoDB operates in a sharded environment, the trusted router typically manages the internal routing metadata that guides query execution across shards. However, the insufficient input validation mechanism allows authenticated users to directly provide these routing fields, effectively circumventing the normal security boundaries that should prevent unauthorized access to data across different user contexts.
The technical implementation of this vulnerability stems from the improper validation of aggregation pipeline inputs within the sharded topology architecture. Standard MongoDB operations rely on the router component to properly populate internal routing information that ensures queries are directed only to appropriate shards based on user permissions and data distribution policies. When an authenticated client can directly manipulate these fields, they gain the ability to construct malicious aggregation pipelines that bypass the normal access control enforcement mechanisms. This creates a scenario where users can potentially access data belonging to other users or system resources that should be restricted.
The operational impact of this vulnerability extends beyond simple unauthorized data access, as it fundamentally undermines the security model of sharded MongoDB deployments. Attackers with valid authentication credentials can construct queries that traverse multiple shards and potentially access information that would normally be isolated based on user permissions. This affects not just individual database records but entire collections or databases that should remain separated according to established access control policies. The vulnerability is particularly concerning in multi-tenant environments where proper data isolation is paramount for security compliance.
Security professionals should recognize this issue as a variant of access control bypass vulnerabilities, specifically aligned with CWE-284 which addresses insufficient access control mechanisms. The attack vector demonstrates characteristics consistent with privilege escalation techniques found in the MITRE ATT&CK framework under the Privilege Escalation category. Organizations using MongoDB Atlas Search in sharded configurations should immediately implement mitigations including restricting direct client access to internal aggregation stages, implementing additional input validation layers, and ensuring proper routing information is only populated by trusted components within the system architecture.
The remediation approach requires administrators to verify that only legitimate router components can populate the internal routing fields used by $search and $searchMeta operations. This involves strengthening input validation mechanisms at the aggregation pipeline level and potentially implementing additional middleware checks that validate the authenticity of routing information before processing search queries. Organizations should also consider implementing network-level restrictions that limit direct access to MongoDB's internal aggregation components while maintaining proper API boundaries for legitimate client applications.