# CVE-2026-81517: MongoDB Connector for BI denial of service via log exhaustion

Source: https://junglewise.ai/threats/cve-2026-81517-mongodb-connector-for-bi-denial-of-service-via-log-exhaustion  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-28. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-81517 · Severity: high · CVSS 7.5 · Published 2026-08-28

MongoDB Connector for BI (mongosqld) is a tool that allows SQL clients to query MongoDB databases. An unauthenticated attacker can exhaust disk storage by repeatedly connecting to the service, causing excessive log writes. When disk space runs out, the service crashes and will not restart until storage is manually restored, resulting in a complete outage for all SQL clients.

Technologies: [MongoDB Connector for BI](https://junglewise.ai/threats/technologies/connector-for-bi). Vendors: [MongoDB](https://junglewise.ai/threats/vendors/mongodb).

## Quick answers

**Is CVE-2026-81517 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-81517 being exploited in the wild.

**How severe is CVE-2026-81517?** High severity, with a CVSS score of 7.5, published 28 August 2026.

**Which products and versions are affected?** MongoDB Connector for BI.

**Is there a fix for CVE-2026-81517?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-81517 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-81517?** Check whether you run MongoDB Connector for BI. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a denial-of-service flaw in the logging mechanism of MongoDB Connector for BI. An unauthenticated remote attacker can trigger repeated connection attempts to the mongosqld port, generating large volumes of routine connection logs. When the configured log path runs out of storage space, log write and rotation operations fail without proper error handling, causing the mongosqld process to terminate. The process will continuously fail on restart until an operator manually frees disk space. The root cause is inadequate error handling for log storage exhaustion, combined with a lack of diagnostic logging to explain the condition.

## Affected products

- MongoDB Connector for BI

## Timeline

- 2026-08-28: disclosed

## References

- [https://www.mongodb.com/docs/bi-connector/current/release-notes/](https://www.mongodb.com/docs/bi-connector/current/release-notes/)

## Related threats

- [MongoDB Connector for BI denial of service via incomplete SASL authentication](https://junglewise.ai/threats/cve-2026-81520-mongodb-connector-for-bi-denial-of-service-via-incomplete-sasl)
- [MongoDB Connector for BI client certificate validation bypass](https://junglewise.ai/threats/cve-2026-81518-mongodb-connector-for-bi-client-certificate-validation-bypass)
- [MongoDB Connector for BI schema-sampling denial of service](https://junglewise.ai/threats/cve-2026-81490-mongodb-connector-for-bi-schema-sampling-denial-of-service)
- [MongoDB Connector for BI SQL injection via unescaped identifiers](https://junglewise.ai/threats/cve-2026-77586-mongodb-connector-for-bi-sql-injection-via-unescaped-identifiers)
- [MongoDB Connector for BI SQL injection in JSON schema validator comments](https://junglewise.ai/threats/cve-2026-77184-mongodb-connector-for-bi-sql-injection-in-json-schema-validator)