CVE-2026-81517: CWE-248: Uncaught Exception in MongoDB BI Connector
Description
CVE-2026-81517 is a high-severity vulnerability in the MongoDB BI Connector (mongosqld) where an unauthenticated attacker can cause the service to terminate by exhausting the storage used for logging. When the log storage is full, subsequent log write or rotation failures trigger an unhandled exception that crashes the mongosqld process, disrupting service for all connected SQL clients. The process continues to fail on startup until storage is restored, and no diagnostic message is recorded to explain the failure.
CVSS v4.0
Score 8.7high
Affected software
MongoDB
BI Connector
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves an uncaught exception (CWE-248) in the MongoDB BI Connector's logging mechanism. An unauthenticated attacker able to reach the mongosqld port can generate excessive connection log entries to fill the configured log storage. When the log write or rotation fails due to lack of storage, the error is not handled properly, causing the mongosqld process to terminate. This results in denial of service for all SQL clients connected through the BI Connector. The service remains down on restart until an operator manually frees storage space. No diagnostic logs are generated to indicate the cause of failure.
Potential Impact
The impact is a denial of service condition affecting all SQL clients connected via the MongoDB BI Connector. An unauthenticated attacker can remotely cause the service to crash and remain unavailable until manual intervention restores log storage availability. This disrupts business operations relying on BI Connector SQL access. There is no indication of data compromise or privilege escalation from the provided information.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, operators should monitor log storage capacity and ensure sufficient disk space is maintained to prevent log write failures. Manual intervention to restore storage is required if the service crashes due to this issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mongodb
- Date Reserved
- 2026-08-26T21:33:02.508Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a9206c9acd9273b4963cf5b
Added to database: 08/28/2026, 22:08:09 UTC
Last enriched: 09/07/2026, 15:26:03 UTC
Last updated: 10/11/2026, 06:48:19 UTC
Views: 77
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