{"id":"CVE-2026-107350","state":"PUBLISHED","title":"Authentication bypass via second StartupMessage during SCRAM authentication in PgBouncer","description":"Improper authentication in PgBouncer 1.17.0 through 1.26.0 allows a remote attacker who knows the password of a user listed in auth_file to log in as any other user that authenticates using SCRAM, including PgBouncer admin users and backend superusers. A second StartupMessage sent during SCRAM authentication against a non-existent database is not rejected and switches the user being logged in as, while the SCRAM exchange is still verified against the keys of the first user.","publishedAt":"2026-10-14T17:34:39.009Z","updatedAt":"2026-10-16T14:18:50.053Z","severity":{"score":8.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"PostgreSQL"},"assigner":"PostgreSQL","products":["n/a PgBouncer"],"affected":[{"vendor":"n/a","product":"PgBouncer","defaultStatus":"unaffected","versions":[{"version":"1.17.0","status":"affected","lessThan":"1.26.1","versionType":"semver"}]}],"references":["https://www.pgbouncer.org/changelog.html"],"weaknesses":["CWE-287"],"ingestedAt":"2026-10-29T20:10:23.711Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/107xxx/CVE-2026-107350.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-107350","state":"PUBLISHED","datePublished":"2026-10-14T17:34:39.009Z","dateUpdated":"2026-10-16T14:18:50.053Z","assignerShortName":"PostgreSQL","assignerOrgId":"f86ef6dc-4d3a-42ad-8f28-e6d5547a5007","dateReserved":"2026-10-07T19:13:32.963Z"},"containers":{"cna":{"title":"Authentication bypass via second StartupMessage during SCRAM authentication in PgBouncer","descriptions":[{"lang":"en","value":"Improper authentication in PgBouncer 1.17.0 through 1.26.0 allows a remote attacker who knows the password of a user listed in auth_file to log in as any other user that authenticates using SCRAM, including PgBouncer admin users and backend superusers. A second StartupMessage sent during SCRAM authentication against a non-existent database is not rejected and switches the user being logged in as, while the SCRAM exchange is still verified against the keys of the first user."}],"affected":[{"vendor":"n/a","product":"PgBouncer","defaultStatus":"unaffected","versions":[{"version":"1.17.0","status":"affected","lessThan":"1.26.1","versionType":"semver"}]}],"references":[{"url":"https://www.pgbouncer.org/changelog.html"}],"metrics":[{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-287","lang":"en","type":"CWE","description":"Improper Authentication"}]}],"providerMetadata":{"shortName":"PostgreSQL","orgId":"f86ef6dc-4d3a-42ad-8f28-e6d5547a5007","dateUpdated":"2026-10-14T17:34:39.009Z"},"configurations":[{"lang":"en","value":"The attacker knows the password of a user that has its password stored in auth_file, and SCRAM authentication is used for both that user and the impersonated user (auth_type = scram-sha-256, auth_type = md5 with SCRAM secrets, or matching hba rules). The impersonated user can be loaded from either auth_file or auth_query."}],"credits":[{"lang":"en","value":"Thanks to Dave Aitel (@daveaitel-openai, OpenAI) for finding and reporting this issue.","type":"finder"}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-107350","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T03:56:50.467564Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T14:18:50.053Z"}}]}}}