GHSA-XVR9-35CR-46V9
Vulnerability from github – Published: 2026-08-28 22:47 – Updated: 2026-08-28 22:47Summary
The connector encodes and decodes all character data assuming the connection character set is UTF-8. A server can change character_set_client mid-session to a non-UTF-8 charset, after which the driver and server interpret the same bytes under different encodings, causing silent data corruption and a client/server charset-confusion mismatch.
Details
The driver encodes and decodes all character data on the assumption that the connection character set is UTF-8. Charset can be changed by commands like SET NAMES... commands.
If the new charset is not UTF-8, the driver continues to read and write UTF-8 while the server interprets the same bytes under a different encoding. The result is silent data corruption and a client/server charset-confusion mismatch. Charset confusion of this kind is also the primitive that can defeat byte-wise quoting/escaping when client and server disagree on a multi-byte encoding.
Impact
Silent data corruption and a client/server encoding mismatch once the connection's charset diverges from UTF-8. Because the mismatch undermines the assumption that quoting/escaping operates on UTF-8 bytes, it belongs to the charset-confusion class that can lead to SQL injection.
Patches
Fixed in 2.7.14, 3.3.5, 3.4.3, and 3.5.9. Upgrade to the patched release on your branch (3.5.x → 3.5.9, 3.4.x → 3.4.3, 3.0/3.1/3.2/3.3.x → 3.3.5, 2.x → 2.7.14). Once the connection is fully initialized, any subsequent charset change to a value that is not utf8 / utf8mb3 / utf8mb4 is rejected: the driver raises a SQLException with SQLState 08000 (connection exception) and closes the connection rather than continuing to exchange data under a mismatched encoding.
Workarounds
There is no reliable application-level workaround.
Credit
Reported by Yalguun Tumenkhuu (@fg0x0).
{
"affected": [
{
"package": {
"ecosystem": "Maven",
"name": "org.mariadb.jdbc:mariadb-java-client"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.7.14"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Maven",
"name": "org.mariadb.jdbc:mariadb-java-client"
},
"ranges": [
{
"events": [
{
"introduced": "3.0.0"
},
{
"fixed": "3.3.5"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Maven",
"name": "org.mariadb.jdbc:mariadb-java-client"
},
"ranges": [
{
"events": [
{
"introduced": "3.4.0"
},
{
"fixed": "3.4.3"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Maven",
"name": "org.mariadb.jdbc:mariadb-java-client"
},
"ranges": [
{
"events": [
{
"introduced": "3.5.0"
},
{
"fixed": "3.5.9"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-55858"
],
"database_specific": {
"cwe_ids": [
"CWE-838"
],
"github_reviewed": true,
"github_reviewed_at": "2026-08-28T22:47:19Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "### Summary\n\nThe connector encodes and decodes all character data assuming the connection character set is UTF-8. A server can change character_set_client mid-session to a non-UTF-8 charset, after which the driver and server interpret the same bytes under different encodings, causing silent data corruption and a client/server charset-confusion mismatch.\n\n### Details\n\nThe driver encodes and decodes all character data on the assumption that the connection character set is UTF-8. \nCharset can be changed by commands like SET NAMES... commands.\n\nIf the new charset is not UTF-8, the driver continues to read and write UTF-8 while the server interprets the same bytes under a different encoding. The result is silent data corruption and a client/server charset-confusion mismatch. Charset confusion of this kind is also the primitive that can defeat byte-wise quoting/escaping when client and server disagree on a multi-byte encoding.\n\n### Impact\n\nSilent data corruption and a client/server encoding mismatch once the connection\u0027s charset diverges from UTF-8. Because the mismatch undermines the assumption that quoting/escaping operates on UTF-8 bytes, it belongs to the charset-confusion class that can lead to SQL injection.\n\n### Patches\n\nFixed in 2.7.14, 3.3.5, 3.4.3, and 3.5.9. Upgrade to the patched release on your branch (3.5.x \u2192 3.5.9, 3.4.x \u2192 3.4.3, 3.0/3.1/3.2/3.3.x \u2192 3.3.5, 2.x \u2192 2.7.14). Once the connection is fully initialized, any subsequent charset change to a value that is not utf8 / utf8mb3 / utf8mb4 is rejected: the driver raises a SQLException with SQLState 08000 (connection exception) and closes the connection rather than continuing to exchange data under a mismatched encoding.\n\n### Workarounds\n\nThere is no reliable application-level workaround.\n\n### Credit\n\nReported by Yalguun Tumenkhuu ([@fg0x0](https://github.com/fg0x0/)).",
"id": "GHSA-xvr9-35cr-46v9",
"modified": "2026-08-28T22:47:19Z",
"published": "2026-08-28T22:47:19Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-xvr9-35cr-46v9"
},
{
"type": "WEB",
"url": "https://github.com/mariadb-corporation/mariadb-connector-j/commit/300716bef1e1d0370a41be7863b88aa2d55fbb69"
},
{
"type": "WEB",
"url": "https://github.com/mariadb-corporation/mariadb-connector-j/commit/7b3c69221b5463ee03472654040b3f6b9e5329c7"
},
{
"type": "WEB",
"url": "https://github.com/mariadb-corporation/mariadb-connector-j/commit/8cfd9df697372ad4ed09fe87a34b34babb6d43d6"
},
{
"type": "WEB",
"url": "https://github.com/mariadb-corporation/mariadb-connector-j/commit/c555c9b477521be0c35c3a5461f9f46681553607"
},
{
"type": "PACKAGE",
"url": "https://github.com/mariadb-corporation/mariadb-connector-j"
},
{
"type": "WEB",
"url": "https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/2.7.14"
},
{
"type": "WEB",
"url": "https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.3.5"
},
{
"type": "WEB",
"url": "https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.3"
},
{
"type": "WEB",
"url": "https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.9"
},
{
"type": "WEB",
"url": "https://jira.mariadb.org/browse/CONJ-1317"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
}
],
"summary": "org.mariadb.jdbc:mariadb-java-client has Inappropriate Encoding for Output Context"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.