CVE-2026-82068 in MongoDB
Summary
by MITRE • 09/08/2026
A security issue in MongoDB Server allows an authenticated user with write privileges to trigger a persistent fatal assertion crash by sending specially crafted retryable write commands. The crash state is durably persisted, causing the server process to repeatedly crash on restart and potentially propagating to additional nodes in a sharded cluster. Manual intervention is required to restore service availability.
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Analysis
by VulDB Data Team • 09/08/2026
The vulnerability described constitutes a critical denial of service condition within MongoDB Server instances that possess authenticated users with write privileges. This flaw arises from the handling of retryable write commands, which are designed to ensure data consistency and durability in distributed database environments by automatically re-executing failed operations under specific conditions. An attacker who has successfully authenticated and obtained sufficient permissions can craft a maliciously structured command that exploits an internal logic error during the processing or persistence phase of these writes. The core technical flaw lies in how the server manages state transitions when encountering malformed input within this retry mechanism, leading to a fatal assertion failure rather than a graceful error return. This indicates a lack of robust input validation and exception handling specifically tailored for edge cases involving transactional integrity checks during write operations.
The operational impact of this vulnerability is severe due to its persistent nature. Unlike typical crashes that might be resolved by simply restarting the service, this specific flaw causes the crash state to be durably persisted to disk. Consequently, when the MongoDB server process attempts to restart after a failure or as part of normal maintenance cycles, it immediately encounters the corrupted state and triggers another fatal assertion. This creates an infinite loop of crashes that renders the database instance completely unavailable without manual intervention. The requirement for manual recovery implies that automated failover mechanisms may also be compromised if they rely on automatic restarts to restore service continuity, thereby extending the downtime significantly beyond what is typical for standard denial-of-service attacks.
In a sharded cluster environment, the risk profile escalates considerably because the corruption can propagate across multiple nodes. If one node in the shard becomes unresponsive due to this persistent crash state, it may trigger cascading failures or load balancing issues that affect other shards and mongos routers within the topology. This propagation capability transforms what might otherwise be an isolated incident into a widespread outage affecting the entire database cluster. The persistence of the error ensures that even if individual nodes are restarted individually, they will continue to fail until the underlying data corruption is manually corrected by a database administrator using specialized recovery tools or commands designed to bypass the faulty assertion logic.
From a threat modeling perspective aligned with industry standards, this vulnerability maps directly to CWE-400: Uncontrolled Resource Consumption and CWE-269: Improper Privilege Management, as it requires authenticated write access but results in resource exhaustion through persistent service unavailability. In terms of the MITRE ATT&CK framework, this behavior is consistent with T1499: Endpoint Denial of Service or more specifically T1505.003: Server Software Component: Stored Remote Code Execution if viewed as a persistence mechanism for denial of service, though it is primarily classified under resource exhaustion techniques that disrupt availability rather than confidentiality or integrity directly. The attack vector requires network access and authentication, placing it in the initial access phase but with immediate impact on availability.
Mitigation strategies must focus on both preventive controls and incident response procedures. Administrators should ensure that MongoDB Server versions are updated to include patches addressing this specific assertion failure if available from the vendor. In environments where patching is not immediately feasible, strict network segmentation and firewall rules can limit access to write operations only to trusted application servers with known good behavior. Implementing rigorous input validation at the application layer before sending commands to the database can also reduce exposure by filtering out malformed payloads that might trigger this flaw. Additionally, regular backups of critical data are essential to facilitate rapid restoration in case manual intervention is required to clear the persistent crash state and restore normal operations.