Vulnerability · Published Aug 28, 2026 · Assigned by GitHub_M
CVE-2026-55859MariaDB Connector/R2DBC: Inappropriate Encoding for Output Context and Improper Encoding or Escaping of Output in org.mariadb:r2dbc-mariadb
Medium 5.9
In plain English
A medium-severity security flaw in mariadb-connector-r2dbc from mariadb-corporation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Maven | org.mariadb:r2dbc-mariadb | 1.4.1 | GHSA-5rqc-86vf-g8r2 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| mariadb-corporation | mariadb-connector-r2dbc | < 1.4.1 |
| org.mariadb | r2dbc-mariadb | < 1.4.1 |
Weakness: CWE-116, CWE-838 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
References
- https://github.com/mariadb-corporation/mariadb-connector-r2dbc/security/advisories/GHSA-5rqc-86vf-g8r2 x_refsource_CONFIRM
- https://github.com/mariadb-corporation/mariadb-connector-r2dbc/commit/38bad9afebc6c581a853656a42f9ebf403b1b1b7 x_refsource_MISC
- https://github.com/mariadb-corporation/mariadb-connector-r2dbc/releases/tag/1.4.1 x_refsource_MISC
- https://jira.mariadb.org/browse/R2DBC-124 x_refsource_MISC