{"id":"CVE-2026-55859","state":"PUBLISHED","title":"MariaDB Connector/R2DBC: Inappropriate Encoding for Output Context and Improper Encoding or Escaping of Output in org.mariadb:r2dbc-mariadb","description":"MariaDB Connector/R2DBC is a non-blocking MariaDB and MySQL client implemented in Java. Prior to 1.4.1, org.mariadb:r2dbc-mariadb encodes and decodes all character data under the assumption that the connection character set is UTF-8. A server can announce a mid-session change to character_set_client through the OK-packet session-state-tracking mechanism, including through SET NAMES executed by a stored routine or trigger, server configuration, or a hostile or man-in-the-middle server. If the new character set is not UTF-8, the driver continues to exchange UTF-8 while the server interprets the same bytes under a different encoding, causing silent data corruption and a client/server charset-confusion mismatch that can defeat byte-wise quoting or escaping. The fix accepts only utf8, utf8mb3, or utf8mb4 after initialization; any other value raises R2dbcNonTransientResourceException with SQLState 08000 and closes the connection. This issue is fixed in version 1.4.1.","publishedAt":"2026-08-28T22:48:41.592Z","updatedAt":"2026-08-31T18:53:25.642Z","severity":{"score":5.9,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["mariadb-corporation mariadb-connector-r2dbc","org.mariadb r2dbc-mariadb"],"affected":[{"vendor":"mariadb-corporation","product":"mariadb-connector-r2dbc","versions":[{"version":"< 1.4.1","status":"affected"}]},{"vendor":"org.mariadb","product":"r2dbc-mariadb","versions":[{"version":"< 1.4.1","status":"affected"}]}],"references":["https://github.com/mariadb-corporation/mariadb-connector-r2dbc/security/advisories/GHSA-5rqc-86vf-g8r2","https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7","https://github.com/mariadb-corporation/mariadb-connector-r2dbc/releases/tag/1.4.1","https://jira.mariadb.org/browse/R2DBC-124"],"weaknesses":["CWE-116","CWE-838"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/55xxx/CVE-2026-55859.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55859","state":"PUBLISHED","datePublished":"2026-08-28T22:48:41.592Z","dateUpdated":"2026-08-31T18:53:25.642Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-17T16:44:40.995Z"},"containers":{"cna":{"title":"MariaDB Connector/R2DBC: Inappropriate Encoding for Output Context and Improper Encoding or Escaping of Output in org.mariadb:r2dbc-mariadb","descriptions":[{"lang":"en","value":"MariaDB Connector/R2DBC is a non-blocking MariaDB and MySQL client implemented in Java. Prior to 1.4.1, org.mariadb:r2dbc-mariadb encodes and decodes all character data under the assumption that the connection character set is UTF-8. A server can announce a mid-session change to character_set_client through the OK-packet session-state-tracking mechanism, including through SET NAMES executed by a stored routine or trigger, server configuration, or a hostile or man-in-the-middle server. If the new character set is not UTF-8, the driver continues to exchange UTF-8 while the server interprets the same bytes under a different encoding, causing silent data corruption and a client/server charset-confusion mismatch that can defeat byte-wise quoting or escaping. The fix accepts only utf8, utf8mb3, or utf8mb4 after initialization; any other value raises R2dbcNonTransientResourceException with SQLState 08000 and closes the connection. This issue is fixed in version 1.4.1."}],"affected":[{"vendor":"mariadb-corporation","product":"mariadb-connector-r2dbc","versions":[{"version":"< 1.4.1","status":"affected"}]},{"vendor":"org.mariadb","product":"r2dbc-mariadb","versions":[{"version":"< 1.4.1","status":"affected"}]}],"references":[{"url":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/security/advisories/GHSA-5rqc-86vf-g8r2","name":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/security/advisories/GHSA-5rqc-86vf-g8r2","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7","name":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7","tags":["x_refsource_MISC"]},{"url":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/releases/tag/1.4.1","name":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/releases/tag/1.4.1","tags":["x_refsource_MISC"]},{"url":"https://jira.mariadb.org/browse/R2DBC-124","name":"https://jira.mariadb.org/browse/R2DBC-124","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.9,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-116","lang":"en","description":"CWE-116: Improper Encoding or Escaping of Output","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-838","lang":"en","description":"CWE-838: Inappropriate Encoding for Output Context","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-28T22:48:41.592Z"},"source":{"advisory":"GHSA-5rqc-86vf-g8r2","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-31T15:21:03.102797Z","id":"CVE-2026-55859","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-31T18:53:25.642Z"}}]}}}