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No exploitation reportedFix availableAwaiting NVD analysis

CVE-2026-55858

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

No exploitation reported by the sources we read.

  • Published2026-08-28
  • Fixed in3.5.9 · 3.4.3 · 3.3.5 · 2.7.14
  • WeaknessCWE-838

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2026-08-2823:17CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-04 03:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-55858?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-55858?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

OSV
mariadb-java-client
BranchAffectedFixed in
3.5≥ 3.5.0, < 3.5.93.5.9
3.4≥ 3.4.0, < 3.4.33.4.3
3.x≥ 3.0.0, < 3.3.53.3.5
2.7< 2.7.142.7.14

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • mariadb-corporation mariadb-connector-j
    Affected
    • = < 2.7.14no fix stated
    • = >= 3.0.0-alpha, < 3.3.5no fix stated
    • = >= 3.4.0, < 3.4.3no fix stated
    • = >= 3.5.0, < 3.5.9no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-08-28

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • airbyte-platform-fips-serverChainguardall versions · fixed in 2.0.0-r7
  • airbyte-platform-serverChainguardall versions · fixed in 2.0.0-r5
  • airbyte-serverChainguardall versions · no fixed version listedand 1 other package
  • camunda-zeebe-8.8Chainguardall versions · fixed in 8.8.36-r2
  • datahub-upgradeMinimOSall versions · fixed in 1.7.0.1-r0and 1 other package
  • debezium-3.3-connector-jdbcChainguardall versions · fixed in 3.3.2-r9
  • debezium-3.4Wolfiall versions · fixed in 3.4.3-r8and 2 other packages
  • debezium-3.4Chainguardall versions · fixed in 3.4.3-r8and 2 other packages

32 more package ranges on OSV.dev

Vendor advisories

  • CVE-2026-55858 Red Hat Product Security1 product fixed · 43 known affected

    org.mariadb.jdbc/mariadb-java-client: MariaDB Connector/J: Silent data corruption due to character set mismatch

    openshift-pipelines/pipelines-console-plugin-pf5-rhel9 as a component of OpenShift Pipelines · openshift-pipelines/pipelines-console-plugin-rhel8 as a component of OpenShift Pipelines · openshift-pipelines/pipelines-console-plugin-rhel9 as a component of OpenShift Pipelines · +40 more

  • RHSA-2026:83082 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat build of Quarkus 3.27.6 release and security update

Full record on NVD

Fix

  1. Update mariadb-java-client to 3.5.9 · 3.4.3 · 3.3.5 · 2.7.14
  2. Vendor fix Red Hat Product Security RHSA-2026:83082 · 1 productBefore applying this update, make sure all previously released errata relevant to your system have been applied. For information about how to apply this update, see https://access.redhat.com/articles/11258.
  3. Workaround from the vendor Red Hat Product Security RHSA-2026:83082 · 1,033 productsUpgrade MariaDB Connector/J to a fixed version (2.7.14, 3.3.5, 3.4.3, or 3.5.9, as appropriate for the branch in use), which rejects any post-initialization character set other than utf8, utf8mb3, or utf8mb4 and closes the connection. Where upgrading is not immediately possible, avoid changing char…
  4. No fix available, says the vendor Red Hat Product Security CVE-2026-55858 · 30 productsFix deferred
  5. No fix available, says the vendor Red Hat Product Security CVE-2026-55858 · 6 productsAffected
  6. No fix planned, says the vendor Red Hat Product Security CVE-2026-55858 · 2 productsOut of support scope
  7. No fix planned, says the vendor Red Hat Product Security CVE-2026-55858 · 5 productsWill not fix

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVE recordread 2026-10-23
  • CISA-ADPSSVC decisionnone2026-09-01
  • OpenCVESSVC decisionnone—
  • CNACVSS 3.15.9known since 2026-10-23
  • CNAweakness (CWE)CWE-838known since 2026-10-23
  • FIRST EPSSEPSS score0.9 %2026-11-03
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryMODERATE2026-08-28

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Published
2026-08-28
Last Modified
2026-09-08
NVD status
Awaiting Analysis
GitHub Advisory
GHSA-xvr9-35cr-46v9

Frequently asked questions

What is CVE-2026-55858?

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.

Is CVE-2026-55858 actively exploited?

Active exploitation of CVE-2026-55858 has not been confirmed. Its EPSS score was 0.9% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-55858?

CVE-2026-55858 has a CVSS v3 base score of 5.9 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N.

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