CVE Catalog

CVE-2026-93394

LowCVSS 3.7
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.32%

23th percentile - higher than 23% of all known CVEs

Summary

A flaw in libmongoc's SCRAM authentication implementation causes the client to continue the handshake and transmit the client proof even when a nonce mismatch is detected in the server's first message. A man-in-the-middle attacker can inject a crafted server-first-message with a controlled salt and low iteration count, then capture the client proof for offline password cracking. The vulnerability is mitigated by TLS, which is standard in production deployments.

Risk Assessment

An unauthorized party in a man-in-the-middle position can capture the client proof and perform offline password cracking, potentially compromising credentials. The risk is significantly reduced when TLS is used.

Recommendation

Upgrade libmongoc to a patched version and enforce TLS with certificate validation for MongoDB connections.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS