CVE-2026-55858: CWE-838: Inappropriate Encoding for Output Context in mariadb-corporation mariadb-connector-j
Description
MariaDB Connector/J versions prior to 2.7.14, 3.3.5, 3.4.3, and 3.5.9 have a vulnerability where the connector incorrectly assumes the connection character set is UTF-8 throughout the session. If the server changes the character_set_client to a non-UTF-8 encoding mid-session, the driver continues to encode/decode as UTF-8, causing silent data corruption and charset confusion. This can defeat client-side escaping and quoting mechanisms. The issue is fixed by restricting allowed character sets after initialization to utf8, utf8mb3, or utf8mb4, with other values causing the connection to close with an error.
CVSS v3.1
Score 5.9medium
Affected software
mariadb-corporation
mariadb-connector-j
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
MariaDB Connector/J, used for Java applications connecting to MariaDB and MySQL, improperly handles mid-session changes to the character_set_client when it changes to a non-UTF-8 encoding. The connector continues to encode and decode protocol text as UTF-8, while the server interprets the bytes under a different encoding. This mismatch causes silent data corruption and can bypass client-side escaping, leading to potential injection or data integrity issues. The vulnerability affects versions prior to 2.7.14, 3.3.5, 3.4.3, and 3.5.9. The fix enforces acceptance of only utf8, utf8mb3, or utf8mb4 character sets after initialization, closing connections that attempt to switch to unsupported encodings.
Potential Impact
This vulnerability can cause silent data corruption and charset confusion between client and server, potentially defeating client-side escaping and quoting protections. This may lead to injection risks or data integrity issues in applications using affected versions of MariaDB Connector/J. There is no impact on confidentiality or availability reported. No known exploits in the wild have been reported.
Mitigation Recommendations
A fix is available in MariaDB Connector/J versions 2.7.14, 3.3.5, 3.4.3, and 3.5.9. Users should upgrade to one of these versions or later to mitigate this issue. No other mitigation is indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-17T16:44:40.995Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a92113dacd9273b496f46ab
Added to database: 08/28/2026, 22:52:45 UTC
Last enriched: 09/07/2026, 15:13:13 UTC
Last updated: 10/12/2026, 06:48:17 UTC
Views: 118
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