{"id":"CVE-2026-55859","title":"MariaDB Connector/R2DBC is a non-blocking MariaDB and MySQL client implemented in Java","summary":"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 s…","severity":"medium","cvss":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","cwe":["CWE-116","CWE-838"],"vendor":"mariadb","product":"org.mariadb:r2dbc-mariadb","affected":["org.mariadb:r2dbc-mariadb < 1.4.1"],"patched":["org.mariadb:r2dbc-mariadb 1.4.1"],"published":"2026-08-28","updated":"2026-09-08","sourceUpdated":"2026-09-08T21:08:37.320","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55859","references":[{"url":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7","label":"security-advisories@github.com"},{"url":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/releases/tag/1.4.1","label":"security-advisories@github.com"},{"url":"https://github.com/mariadb-corporation/mariadb-connector-r2dbc/security/advisories/GHSA-5rqc-86vf-g8r2","label":"security-advisories@github.com"},{"url":"https://jira.mariadb.org/browse/R2DBC-124","label":"security-advisories@github.com"},{"url":"https://github.com/advisories/GHSA-5rqc-86vf-g8r2"}],"tags":["nvd","ghsa","maven"],"epss":0.00297,"epssPercentile":0.22602,"aliases":["GHSA-5rqc-86vf-g8r2"],"ecosystem":"maven","ingestedAt":"2026-08-28T23:26:57.313Z","slug":"CVE-2026-55859","body":"## Overview\n\nMariaDB 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-55859)\n\nAffected packages:\n\n- `org.mariadb:r2dbc-mariadb < 1.4.1`\n\nPatched in:\n\n- `org.mariadb:r2dbc-mariadb 1.4.1`\n\nSource: https://github.com/advisories/GHSA-5rqc-86vf-g8r2","depth":"sunlit","depthScore":33,"depthScoreParts":{"impact":32.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}