# CVE-2026-55858

## Summary

- **CVE ID:** CVE-2026-55858
- **Severity:** MEDIUM
- **CVSS Score:** 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N)
- **CWE:** CWE-838
- **Published:** Aug 28, 2026
- **Last Modified:** Sep 1, 2026

## 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.

## Affected Products

- mariadb-corporation — mariadb-connector-j (< 2.7.14)
- mariadb-corporation — mariadb-connector-j (>= 3.0.0-alpha, < 3.3.5)
- mariadb-corporation — mariadb-connector-j (>= 3.4.0, < 3.4.3)
- mariadb-corporation — mariadb-connector-j (>= 3.5.0, < 3.5.9)

## References

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

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.34%
- **EPSS Percentile:** 27.5

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-12._