# CVE-2026-18888: MongoDB BI Connector ODBC Driver buffer overflow in float-to-text conversion

Source: https://junglewise.ai/threats/cve-2026-18888-mongodb-bi-connector-odbc-driver-buffer-overflow-in-float-to-text  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-12. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-18888 · Severity: medium · CVSS 6.5 · Published 2026-08-12

The MongoDB BI Connector ODBC Driver, used to query MongoDB databases from BI tools and applications, does not properly validate the size of floating-point numbers when converting them to text. An attacker who can insert data into a collection could store a specially crafted large floating-point value that, when read through the connector, causes the driver to write beyond allocated memory and crash the reading application.

Technologies: [MongoDB Bi Connector Odbc Driver](https://junglewise.ai/threats/technologies/bi-connector-odbc-driver). Vendors: [MongoDB](https://junglewise.ai/threats/vendors/mongodb).

## Quick answers

**Is CVE-2026-18888 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-18888 being exploited in the wild.

**How severe is CVE-2026-18888?** Medium severity, with a CVSS score of 6.5, published 12 August 2026.

**Which products and versions are affected?** MongoDB Bi Connector Odbc Driver before 1.4.9.

**Is there a fix for CVE-2026-18888?** A patch was published on 2026-08-06: Version 1.4.9 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-18888 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-18888?** Check whether you run MongoDB Bi Connector Odbc Driver at an affected version. 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 classic buffer overflow in the ODBC driver's floating-point to text conversion logic. The driver converts floating point values without bounds-checking, allowing large values to overflow the destination buffer and corrupt adjacent memory. The attack requires the ability to store malicious data in a MongoDB collection that is then queried through the BI Connector; network-based remote exploitation is not direct, but depends on application context. An attacker with write access to MongoDB can reliably crash consuming applications, leading to denial of service. A patch was released in version 1.4.9 that clamps large floats during string conversion.

## Affected products

- MongoDB BI Connector ODBC Driver before 1.4.9

## Timeline

- 2026-08-12: disclosed
- 2026-08-06: patched: Version 1.4.9 released

## References

- [https://github.com/mongodb/mongo-bi-connector-odbc-driver/releases/tag/v1.4.9](https://github.com/mongodb/mongo-bi-connector-odbc-driver/releases/tag/v1.4.9)

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