{"id":"UBUNTU-CVE-2026-93394","details":"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.","modified":"2026-09-23T23:40:09Z","published":"2026-09-17T21:17:00Z","upstream":["CVE-2026-93394"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-93394"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-93394"},{"type":"REPORT","url":"https://jira.mongodb.org/browse/CDRIVER-6315"}],"affected":[{"package":{"name":"mongo-c-driver","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/mongo-c-driver?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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"],"ecosystem_specific":{"binaries":[{"binary_name":"libbson-1.0-0","binary_version":"1.16.1-1ubuntu0.1~esm1"},{"binary_name":"libmongoc-1.0-0","binary_version":"1.16.1-1ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93394.json"}},{"package":{"name":"mongo-c-driver","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/mongo-c-driver?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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"],"ecosystem_specific":{"binaries":[{"binary_name":"libbson-1.0-0","binary_version":"1.21.0-1ubuntu0.1~esm1"},{"binary_name":"libmongoc-1.0-0","binary_version":"1.21.0-1ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93394.json"}},{"package":{"name":"mongo-c-driver","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/mongo-c-driver?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"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"],"ecosystem_specific":{"binaries":[{"binary_version":"1.26.0-1.1ubuntu2+esm1","binary_name":"libbson-1.0-0t64"},{"binary_version":"1.26.0-1.1ubuntu2+esm1","binary_name":"libmongoc-1.0-0t64"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93394.json"}},{"package":{"name":"mongo-c-driver","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/mongo-c-driver?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.30.4-1ubuntu1","2.2.0-1","2.2.1-1","2.2.2-1"],"ecosystem_specific":{"binaries":[{"binary_name":"libbson2-2","binary_version":"2.2.2-1"},{"binary_name":"libmongoc2-2","binary_version":"2.2.2-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93394.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N"},{"type":"CVSS_V4","score":"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"},{"type":"Ubuntu","score":"medium"}]}