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CVE-2026-93394

CVE-2026-93394 · libmongoc SCRAM client nonce-validation bypass

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 6.3 · Medium · EPSS 0.3% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • c driver

    Versions
    • ≥ 2.0.0, < 2.3.2: Affected (semver)

    Update to 2.3.2

  • mongo-c-driver Debian:12

    Versions
    • 1.23.1-1
    • 1.23.1-1+deb12u1
    • 1.23.1-1+deb12u2
    • 1.23.1-1+deb12u3
    • 1.24.1-1
    • 1.24.2-1
    • 1.24.3-1
    • 1.24.4-1
    • 1.25.0-1
    • 1.25.1-1
    • 1.25.2-1
    • 1.25.4-1
    • 1.25.4-1.1~exp1
    • 1.26.0-1
    • 1.26.0-1.1
    • 1.26.0-1.1~exp1
    • 1.26.1-1
    • 1.26.2-1
    • 1.27.0-1
    • 1.27.1-1
    • 1.27.2-1
    • 1.27.3-1
    • 1.27.4-1
    • 1.27.5-1
    • 1.27.6-1
    • 1.28.0-1
    • 1.28.1-1
    • 1.29.0-1
    • 1.29.1-1
    • 1.29.2-1
    • 1.30.0-1
    • 1.30.1-1
    • 1.30.2-1
    • 1.30.3-1
    • 1.30.4-1
    • 2.0.2-1
    • 2.1.0-1
    • 2.1.1-1
    • 2.1.2-1
    • 2.2.0-1
    • 2.2.1-1
    • 2.2.2-1
    • 2.2.3-1
    • 2.2.4-1
    • 2.3.0-1
    • 2.3.1-1
    • 2.3.2-1
    • 2.3.3-1
    • 2.4.0-1
    • 2.5.0-1
    • 2.5.1-1
    • 2.5.2-1
    • 2.5.3-1
    • 2.5.5-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mongo-c-driver Debian:13

    Versions
    • 1.30.4-1
    • 1.30.4-1+deb13u1
    • 1.30.4-1+deb13u2
    • 1.30.4-1+deb13u3
    • 2.0.2-1
    • 2.1.0-1
    • 2.1.1-1
    • 2.1.2-1
    • 2.2.0-1
    • 2.2.1-1
    • 2.2.2-1
    • 2.2.3-1
    • 2.2.4-1
    • 2.3.0-1
    • 2.3.1-1
    • 2.3.2-1
    • 2.3.3-1
    • 2.4.0-1
    • 2.5.0-1
    • 2.5.1-1
    • 2.5.2-1
    • 2.5.3-1
    • 2.5.5-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mongo-c-driver Debian:14

    Versions
    • 1.30.4-1
    • 2.0.2-1
    • 2.1.0-1
    • 2.1.1-1
    • 2.1.2-1
    • 2.2.0-1
    • 2.2.1-1
    • 2.2.2-1
    • 2.2.3-1
    • 2.2.4-1
    • 2.3.0-1
    • 2.3.1-1
    • 2.3.2-1
    • 2.3.3-1
    Affected ranges
    • ECOSYSTEM: < 2.4.0-1

    Update to 2.4.0-1

  • mongo-c-driver Ubuntu:Pro:20.04:LTS

    Versions
    • 1.15.0-1
    • 1.15.1-1
    • 1.15.2-1
    • 1.16.0-1
    • 1.16.1-1
    • 1.16.1-1build1
    • 1.16.1-1build2
    • 1.16.1-1ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mongo-c-driver Ubuntu:Pro:22.04:LTS

    Versions
    • 1.18.0-1
    • 1.19.1-1
    • 1.19.2-1
    • 1.20.0-1
    • 1.20.0-1build1
    • 1.20.1-1
    • 1.21.0-1
    • 1.21.0-1build1
    • 1.21.0-1ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mongo-c-driver Ubuntu:Pro:24.04:LTS

    Versions
    • 1.24.3-1
    • 1.24.4-1
    • 1.25.1-1
    • 1.25.2-1
    • 1.25.4-1
    • 1.26.0-1
    • 1.26.0-1.1ubuntu1
    • 1.26.0-1.1ubuntu2
    • 1.26.0-1.1ubuntu2+esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • mongo-c-driver Ubuntu:26.04:LTS

    Versions
    • 1.30.4-1ubuntu1
    • 2.2.0-1
    • 2.2.1-1
    • 2.2.2-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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