# CVE-2026-93394: mongo-c-driver: A flaw in libmongoc's SCRAM authentication implementation caused the client to continue the authentication handshake...

CVE-2026-93394 is fixed in mongo-c-driver on 1 platform by DEBIAN-CVE-2026-93394 (version 2.4.0-1), released September 18, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-93394
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0032
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 17, 2026

## Description

A flaw in libmongoc's SCRAM authentication implementation caused the client to continue the authentication handshake and transmit the client proof even when a nonce mismatch was detected in the server's first message. An unauthorized party with a man-in-the-middle position could exploit this by injecting a crafted server-first-message containing a controlled salt and low iteration count, then capturing the resulting client proof to perform offline password cracking. This vulnerability is mitigated by TLS, which is standard in production deployments.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | mongo-c-driver Debian 14 | 2.4.0-1 | [DEBIAN-CVE-2026-93394](https://patchblox.com/security/data/fix/linux/debian-cve-2026-93394.md) | Sep 18, 2026 |

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Data as of 2026-11-09T07:25:28Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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