{"id":"CVE-2026-93394","title":"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","summary":"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 par…","severity":"low","cvss":3.7,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","cwe":["CWE-303"],"vendor":"mongodb","product":"c_driver","affected":["c_driver >= 2.0.0, < 2.3.2"],"patched":["c_driver 2.3.2"],"published":"2026-09-17","updated":"2026-09-25","sourceUpdated":"2026-09-25T20:33:17.027","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-93394","references":[{"url":"https://jira.mongodb.org/browse/CDRIVER-6315","label":"cna@mongodb.com"}],"tags":["nvd","cve.org"],"epss":0.00321,"epssPercentile":0.25004,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-18T14:27:52.100964Z"},"ingestedAt":"2026-09-17T21:29:16.992Z","slug":"CVE-2026-93394","body":"## Overview\n\nA 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.\n\n## Affected\n\n- `c_driver >= 2.0.0, < 2.3.2`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `c_driver 2.3.2`","depth":"sunlit","depthScore":20,"depthScoreParts":{"impact":20.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}