{"id":"CVE-2026-55859","summary":"MariaDB Connector/R2DBC: Inappropriate Encoding for Output Context and Improper Encoding or Escaping of Output in org.mariadb:r2dbc-mariadb","details":"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.","aliases":["GHSA-5rqc-86vf-g8r2"],"modified":"2026-08-30T08:17:29.750374Z","published":"2026-08-28T22:48:41.592Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-116","CWE-838"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55859.json"},"references":[{"type":"WEB","url":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/releases/tag/1.4.1"},{"type":"WEB","url":"https://jira.mariadb.org/browse/R2DBC-124"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55859.json"},{"type":"ADVISORY","url":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/security/advisories/GHSA-5rqc-86vf-g8r2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55859"},{"type":"FIX","url":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc","events":[{"introduced":"0"},{"fixed":"38bad9afebc6c581a853656a42f9ebf403b1b1b7"},{"fixed":"a82d2658aa0f081e2967521eb45ba91165f7ecd5"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"1.4.1"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["1.3.0","1.2.2","1.4.0","1.2.1","1.2.0","1.1.0-beta","1.0.0","0.8.2","0.8.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55859.json","vanir_signatures_modified":"2026-08-30T08:17:29Z","vanir_signatures":[{"signature_version":"v1","source":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7","target":{"file":"src/test/java/org/mariadb/r2dbc/integration/ConnectionTest.java"},"deprecated":false,"digest":{"line_hashes":["175449461016011700323899743789300643104","151865224896235913604284388705509472048","49470070527222200272430178483448313444"],"threshold":0.9},"id":"CVE-2026-55859-0250c75a","signature_type":"Line"},{"signature_type":"Line","signature_version":"v1","source":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7","target":{"file":"src/main/java/org/mariadb/r2dbc/message/Context.java"},"deprecated":false,"digest":{"line_hashes":["311376241794860913811684866166919676769","299254488554560412267049599103447553433"],"threshold":0.9},"id":"CVE-2026-55859-055c20f1"},{"signature_version":"v1","source":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7","target":{"file":"src/main/java/org/mariadb/r2dbc/MariadbConnectionFactory.java","function":"connectToSocket"},"deprecated":false,"digest":{"function_hash":"97501225860178295876014078662935128876","length":414},"id":"CVE-2026-55859-267fa781","signature_type":"Function"},{"deprecated":false,"digest":{"function_hash":"96410674812635403064961704368511768443","length":1795},"id":"CVE-2026-55859-4d554f75","signature_type":"Function","signature_version":"v1","source":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7","target":{"file":"src/main/java/org/mariadb/r2dbc/client/SimpleClient.java","function":"redirect"}},{"deprecated":false,"digest":{"function_hash":"233672716502376929720775774745702138095","length":480},"id":"CVE-2026-55859-5de8563d","signature_type":"Function","signature_version":"v1","source":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7","target":{"file":"src/main/java/org/mariadb/r2dbc/client/SimpleClient.java","function":"handleConnectionError"}},{"deprecated":false,"digest":{"line_hashes":["242356496912250413467939147856499549619","260022072441143881492123846506832677630","159077364659536727243804022826779482619","285092228571018649786998077259903249197","120889995672586767923701201471548033279"],"threshold":0.9},"id":"CVE-2026-55859-680234b8","signature_type":"Line","signature_version":"v1","source":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7","target":{"file":"src/main/java/org/mariadb/r2dbc/HaMode.java"}},{"signature_type":"Function","signature_version":"v1","source":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7","target":{"file":"src/main/java/org/mariadb/r2dbc/message/server/OkPacket.java","function":"decode"},"deprecated":false,"digest":{"function_hash":"299232000241909000197794677479643065559","length":1790},"id":"CVE-2026-55859-814f2bad"},{"digest":{"line_hashes":["261264049692410327612566317365309902085","183746314865237572193705111922430388884","46831815411059886601112132982326655164","2565135421973799176815091559569882348","54904543050355290851865391174581538128","337103227735773347348156008315922513185","17040833038869631590013145343535793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