# CVE-2026-88035: mongo-c-driver: A size check in the client-side authentication path of the MongoDB C Driver can wrap around, so an unusually large us...

CVE-2026-88035 is fixed in mongo-c-driver on 1 platform by DEBIAN-CVE-2026-88035 (version 2.5.3-1), released September 17, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-88035
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0010
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 10, 2026

## Description

A size check in the client-side authentication path of the MongoDB C Driver can wrap around, so an unusually large user-name value is accepted and copied past the end of a small buffer. A party able to set the driver's connection settings may cause the application that embeds the driver to terminate unexpectedly. Reaching this code requires a build in which the optional external SASL authentication backend is present and a connection configured to use it.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | mongo-c-driver Debian 14 | 2.5.3-1 | [DEBIAN-CVE-2026-88035](https://patchblox.com/security/data/fix/linux/debian-cve-2026-88035.md) | Sep 17, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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