{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-93394", "assignerOrgId": "a39b4221-9bd0-4244-95fc-f3e2e07f1deb", "state": "PUBLISHED", "assignerShortName": "mongodb", "dateReserved": "2026-09-17T20:11:00.595Z", "datePublished": "2026-09-17T20:31:27.875Z", "dateUpdated": "2026-09-17T20:31:27.875Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "a39b4221-9bd0-4244-95fc-f3e2e07f1deb", "shortName": "mongodb", "dateUpdated": "2026-09-17T20:31:27.875Z"}, "title": "libmongoc SCRAM client nonce-validation bypass", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-303", "description": "CWE-303: Incorrect Implementation of Authentication Algorithm", "type": "CWE"}]}], "affected": [{"vendor": "MongoDB Inc.", "product": "C Driver", "versions": [{"status": "affected", "version": "2.0.0", "lessThan": "2.3.2", "versionType": "semver"}], "defaultStatus": "unaffected"}], "descriptions": [{"lang": "en", "value": "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.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "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."}]}], "references": [{"url": "https://jira.mongodb.org/browse/CDRIVER-6315"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "LOW", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "MEDIUM", "baseScore": 6.3, "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"}}, {"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE", "baseSeverity": "LOW", "baseScore": 3.7, "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N"}}], "source": {"discovery": "INTERNAL"}, "x_generator": {"engine": "Vulnogram 1.0.5"}}}}

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